diff --git a/.eslintrc.yml b/.eslintrc.yml
index c11ebb19..41066667 100644
--- a/.eslintrc.yml
+++ b/.eslintrc.yml
@@ -4,6 +4,8 @@
 
 root: true
 extends: "@jsdevtools"
+parserOptions:
+  sourceType: module
 env:
   node: true
   browser: true
diff --git a/karma.conf.js b/karma.conf.js
index 0f9b7050..f224911a 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -2,8 +2,6 @@
 // https://karma-runner.github.io/0.12/config/configuration-file.html
 // https://jstools.dev/karma-config/
 
-"use strict";
-
 const { karmaConfig } = require("@jsdevtools/karma-config");
 const { host } = require("@jsdevtools/host-environment");
 
diff --git a/lib/bundle.js b/lib/bundle.js
index d5578bf1..c4a21444 100644
--- a/lib/bundle.js
+++ b/lib/bundle.js
@@ -1,10 +1,8 @@
-"use strict";
+import $Ref from "./ref";
+import Pointer from "./pointer";
+import url from "./util/url";
 
-const $Ref = require("./ref");
-const Pointer = require("./pointer");
-const url = require("./util/url");
-
-module.exports = bundle;
+export default bundle;
 
 /**
  * Bundles all external JSON references into the main JSON schema, thus resulting in a schema that
diff --git a/lib/dereference.js b/lib/dereference.js
index f6b2b203..7d11abc9 100644
--- a/lib/dereference.js
+++ b/lib/dereference.js
@@ -1,11 +1,10 @@
-"use strict";
+import $Ref from "./ref";
+import Pointer from "./pointer";
+import { ono } from "@jsdevtools/ono";
 
-const $Ref = require("./ref");
-const Pointer = require("./pointer");
-const { ono } = require("@jsdevtools/ono");
-const url = require("./util/url");
+import url from "./util/url";
 
-module.exports = dereference;
+export default dereference;
 
 /**
  * Crawls the JSON schema, finds all JSON references, and dereferences them.
diff --git a/lib/index.d.ts b/lib/index.d.ts
index 547f27fe..db696195 100644
--- a/lib/index.d.ts
+++ b/lib/index.d.ts
@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
 import { JSONSchema4, JSONSchema4Type, JSONSchema6, JSONSchema6Type, JSONSchema7, JSONSchema7Type } from "json-schema";
 
 export = $RefParser;
diff --git a/lib/index.js b/lib/index.js
index fb5d5f32..ddc26194 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -1,26 +1,34 @@
 /* eslint-disable no-unused-vars */
-"use strict";
+import $Refs from "./refs";
+import _parse from "./parse";
+import normalizeArgs from "./normalize-args";
+import resolveExternal from "./resolve-external";
+import _bundle from "./bundle";
+import _dereference from "./dereference";
+import url from "./util/url";
+import {
+  InvalidPointerError,
+  isHandledError,
+  JSONParserError,
+  JSONParserErrorGroup,
+  MissingPointerError,
+  ParserError,
+  ResolverError,
+  UnmatchedParserError,
+  UnmatchedResolverError
+} from "./util/errors";
 
-const $Refs = require("./refs");
-const _parse = require("./parse");
-const normalizeArgs = require("./normalize-args");
-const resolveExternal = require("./resolve-external");
-const _bundle = require("./bundle");
-const _dereference = require("./dereference");
-const url = require("./util/url");
-const { JSONParserError, InvalidPointerError, MissingPointerError, ResolverError, ParserError, UnmatchedParserError, UnmatchedResolverError, isHandledError, JSONParserErrorGroup } = require("./util/errors");
-const maybe = require("call-me-maybe");
-const { ono } = require("@jsdevtools/ono");
+import maybe from "call-me-maybe";
+import { ono } from "@jsdevtools/ono";
 
-module.exports = $RefParser;
-module.exports.default = $RefParser;
-module.exports.JSONParserError = JSONParserError;
-module.exports.InvalidPointerError = InvalidPointerError;
-module.exports.MissingPointerError = MissingPointerError;
-module.exports.ResolverError = ResolverError;
-module.exports.ParserError = ParserError;
-module.exports.UnmatchedParserError = UnmatchedParserError;
-module.exports.UnmatchedResolverError = UnmatchedResolverError;
+export default $RefParser;
+export { JSONParserError };
+export { InvalidPointerError };
+export { MissingPointerError };
+export { ResolverError };
+export { ParserError };
+export { UnmatchedParserError };
+export { UnmatchedResolverError };
 
 /**
  * This class parses a JSON schema, builds a map of its JSON references and their resolved values,
diff --git a/lib/normalize-args.js b/lib/normalize-args.js
index 1d48fe4d..1fafcdbb 100644
--- a/lib/normalize-args.js
+++ b/lib/normalize-args.js
@@ -1,8 +1,6 @@
-"use strict";
+import Options from "./options";
 
-const Options = require("./options");
-
-module.exports = normalizeArgs;
+export default normalizeArgs;
 
 /**
  * Normalizes the given arguments, accounting for optional args.
diff --git a/lib/options.js b/lib/options.js
index 199362a6..a3c8dada 100644
--- a/lib/options.js
+++ b/lib/options.js
@@ -1,14 +1,11 @@
-/* eslint lines-around-comment: [2, {beforeBlockComment: false}] */
-"use strict";
+import jsonParser from "./parsers/json";
+import yamlParser from "./parsers/yaml";
+import textParser from "./parsers/text";
+import binaryParser from "./parsers/binary";
+import fileResolver from "./resolvers/file";
+import httpResolver from "./resolvers/http";
 
-const jsonParser = require("./parsers/json");
-const yamlParser = require("./parsers/yaml");
-const textParser = require("./parsers/text");
-const binaryParser = require("./parsers/binary");
-const fileResolver = require("./resolvers/file");
-const httpResolver = require("./resolvers/http");
-
-module.exports = $RefParserOptions;
+export default $RefParserOptions;
 
 /**
  * Options that determine how JSON schemas are parsed, resolved, and dereferenced.
diff --git a/lib/parse.js b/lib/parse.js
index b9160df6..b997b5ef 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -1,11 +1,10 @@
-"use strict";
+import { ono } from "@jsdevtools/ono";
 
-const { ono } = require("@jsdevtools/ono");
-const url = require("./util/url");
-const plugins = require("./util/plugins");
-const { ResolverError, ParserError, UnmatchedParserError, UnmatchedResolverError, isHandledError } = require("./util/errors");
+import url from "./util/url";
+import plugins from "./util/plugins";
+import { isHandledError, ParserError, ResolverError, UnmatchedParserError, UnmatchedResolverError } from "./util/errors";
 
-module.exports = parse;
+export default parse;
 
 /**
  * Reads and parses the specified file path or URL.
diff --git a/lib/parsers/binary.js b/lib/parsers/binary.js
index be15073c..141fc3a8 100644
--- a/lib/parsers/binary.js
+++ b/lib/parsers/binary.js
@@ -1,8 +1,6 @@
-"use strict";
-
 let BINARY_REGEXP = /\.(jpeg|jpg|gif|png|bmp|ico)$/i;
 
-module.exports = {
+export default {
   /**
    * The order that this parser will run, in relation to other parsers.
    *
diff --git a/lib/parsers/json.js b/lib/parsers/json.js
index 34dd986f..0ed9b76f 100644
--- a/lib/parsers/json.js
+++ b/lib/parsers/json.js
@@ -1,8 +1,6 @@
-"use strict";
+import { ParserError } from "../util/errors";
 
-const { ParserError } = require("../util/errors");
-
-module.exports = {
+export default {
   /**
    * The order that this parser will run, in relation to other parsers.
    *
diff --git a/lib/parsers/text.js b/lib/parsers/text.js
index 03bcd96b..f235c97a 100644
--- a/lib/parsers/text.js
+++ b/lib/parsers/text.js
@@ -1,10 +1,8 @@
-"use strict";
-
-const { ParserError } = require("../util/errors");
+import { ParserError } from "../util/errors";
 
 let TEXT_REGEXP = /\.(txt|htm|html|md|xml|js|min|map|css|scss|less|svg)$/i;
 
-module.exports = {
+export default {
   /**
    * The order that this parser will run, in relation to other parsers.
    *
diff --git a/lib/parsers/yaml.js b/lib/parsers/yaml.js
index 94c4eca0..f2307a86 100644
--- a/lib/parsers/yaml.js
+++ b/lib/parsers/yaml.js
@@ -1,10 +1,8 @@
-"use strict";
+import { ParserError } from "../util/errors";
 
-const { ParserError } = require("../util/errors");
-const yaml = require("js-yaml");
-const { JSON_SCHEMA } = require("js-yaml");
+import yaml, { JSON_SCHEMA } from "js-yaml";
 
-module.exports = {
+export default {
   /**
    * The order that this parser will run, in relation to other parsers.
    *
diff --git a/lib/pointer.js b/lib/pointer.js
index 299b2215..b8344ac7 100644
--- a/lib/pointer.js
+++ b/lib/pointer.js
@@ -1,10 +1,9 @@
-"use strict";
+import $Ref from "./ref";
+import url from "./util/url";
+import { InvalidPointerError, isHandledError, JSONParserError, MissingPointerError } from "./util/errors";
 
-module.exports = Pointer;
+export default Pointer;
 
-const $Ref = require("./ref");
-const url = require("./util/url");
-const { JSONParserError, InvalidPointerError, MissingPointerError, isHandledError } = require("./util/errors");
 const slashes = /\//g;
 const tildes = /~/g;
 const escapedSlash = /~1/g;
diff --git a/lib/ref.js b/lib/ref.js
index b6693795..b8d6fec0 100644
--- a/lib/ref.js
+++ b/lib/ref.js
@@ -1,10 +1,8 @@
-"use strict";
+import Pointer from "./pointer";
+import { InvalidPointerError, isHandledError, normalizeError } from "./util/errors";
+import url from "./util/url";
 
-module.exports = $Ref;
-
-const Pointer = require("./pointer");
-const { InvalidPointerError, isHandledError, normalizeError } = require("./util/errors");
-const { safePointerToPath, stripHash, getHash } = require("./util/url");
+export default $Ref;
 
 /**
  * This class represents a single JSON reference and its resolved value.
@@ -129,13 +127,13 @@ $Ref.prototype.resolve = function (path, options, friendlyPath, pathFromRoot) {
     }
 
     if (err.path === null) {
-      err.path = safePointerToPath(getHash(pathFromRoot));
+      err.path = url.safePointerToPath(url.getHash(pathFromRoot));
     }
 
     if (err instanceof InvalidPointerError) {
       // this is a special case - InvalidPointerError is thrown when dereferencing external file,
       // but the issue is caused by the source file that referenced the file that undergoes dereferencing
-      err.source = decodeURI(stripHash(pathFromRoot));
+      err.source = decodeURI(url.stripHash(pathFromRoot));
     }
 
     this.addError(err);
diff --git a/lib/refs.js b/lib/refs.js
index b487eb78..1b56f62a 100644
--- a/lib/refs.js
+++ b/lib/refs.js
@@ -1,10 +1,9 @@
-"use strict";
+import { ono } from "@jsdevtools/ono";
 
-const { ono } = require("@jsdevtools/ono");
-const $Ref = require("./ref");
-const url = require("./util/url");
+import $Ref from "./ref";
+import url from "./util/url";
 
-module.exports = $Refs;
+export default $Refs;
 
 /**
  * This class is a map of JSON references and their resolved values.
diff --git a/lib/resolve-external.js b/lib/resolve-external.js
index 9af29bb2..af192fda 100644
--- a/lib/resolve-external.js
+++ b/lib/resolve-external.js
@@ -1,12 +1,10 @@
-"use strict";
+import $Ref from "./ref";
+import Pointer from "./pointer";
+import parse from "./parse";
+import url from "./util/url";
+import { isHandledError } from "./util/errors";
 
-const $Ref = require("./ref");
-const Pointer = require("./pointer");
-const parse = require("./parse");
-const url = require("./util/url");
-const { isHandledError } = require("./util/errors");
-
-module.exports = resolveExternal;
+export default resolveExternal;
 
 /**
  * Crawls the JSON schema, finds all external JSON references, and resolves their values.
diff --git a/lib/resolvers/file.js b/lib/resolvers/file.js
index 45577ad7..8a38eb88 100644
--- a/lib/resolvers/file.js
+++ b/lib/resolvers/file.js
@@ -1,10 +1,10 @@
-"use strict";
-const fs = require("fs");
-const { ono } = require("@jsdevtools/ono");
-const url = require("../util/url");
-const { ResolverError } = require("../util/errors");
+import fs from "fs";
+import { ono } from "@jsdevtools/ono";
 
-module.exports = {
+import url from "../util/url";
+import { ResolverError } from "../util/errors";
+
+export default {
   /**
    * The order that this resolver will run, in relation to other resolvers.
    *
diff --git a/lib/resolvers/http.js b/lib/resolvers/http.js
index eaadd2de..43ca20df 100644
--- a/lib/resolvers/http.js
+++ b/lib/resolvers/http.js
@@ -1,12 +1,11 @@
-"use strict";
+import http from "http";
+import https from "https";
+import { ono } from "@jsdevtools/ono";
 
-const http = require("http");
-const https = require("https");
-const { ono } = require("@jsdevtools/ono");
-const url = require("../util/url");
-const { ResolverError } = require("../util/errors");
+import url from "../util/url";
+import { ResolverError } from "../util/errors";
 
-module.exports = {
+export default {
   /**
    * The order that this resolver will run, in relation to other resolvers.
    *
diff --git a/lib/util/errors.js b/lib/util/errors.js
index 4cdb1c0a..3201f33a 100644
--- a/lib/util/errors.js
+++ b/lib/util/errors.js
@@ -1,10 +1,8 @@
-"use strict";
+import { Ono } from "@jsdevtools/ono";
 
-const { Ono } = require("@jsdevtools/ono");
+import url from "./url";
 
-const { stripHash, toFileSystemPath } = require("./url");
-
-const JSONParserError = exports.JSONParserError = class JSONParserError extends Error {
+export class JSONParserError extends Error {
   constructor (message, source) {
     super();
 
@@ -19,16 +17,16 @@ const JSONParserError = exports.JSONParserError = class JSONParserError extends
   get footprint () {
     return `${this.path}+${this.source}+${this.code}+${this.message}`;
   }
-};
+}
 
 setErrorName(JSONParserError);
 
-const JSONParserErrorGroup = exports.JSONParserErrorGroup = class JSONParserErrorGroup extends Error {
+export class JSONParserErrorGroup extends Error {
   constructor (parser) {
     super();
 
     this.files = parser;
-    this.message = `${this.errors.length} error${this.errors.length > 1 ? "s" : ""} occurred while reading '${toFileSystemPath(parser.$refs._root$Ref.path)}'`;
+    this.message = `${this.errors.length} error${this.errors.length > 1 ? "s" : ""} occurred while reading '${url.toFileSystemPath(parser.$refs._root$Ref.path)}'`;
 
     Ono.extend(this);
   }
@@ -48,31 +46,31 @@ const JSONParserErrorGroup = exports.JSONParserErrorGroup = class JSONParserErro
   get errors () {
     return JSONParserErrorGroup.getParserErrors(this.files);
   }
-};
+}
 
 setErrorName(JSONParserErrorGroup);
 
-const ParserError = exports.ParserError = class ParserError extends JSONParserError {
+export class ParserError extends JSONParserError {
   constructor (message, source) {
     super(`Error parsing ${source}: ${message}`, source);
 
     this.code = "EPARSER";
   }
-};
+}
 
 setErrorName(ParserError);
 
-const UnmatchedParserError = exports.UnmatchedParserError = class UnmatchedParserError extends JSONParserError {
+export class UnmatchedParserError extends JSONParserError {
   constructor (source) {
     super(`Could not find parser for "${source}"`, source);
 
     this.code = "EUNMATCHEDPARSER";
   }
-};
+}
 
 setErrorName(UnmatchedParserError);
 
-const ResolverError = exports.ResolverError = class ResolverError extends JSONParserError {
+export class ResolverError extends JSONParserError {
   constructor (ex, source) {
     super(ex.message || `Error reading file "${source}"`, source);
 
@@ -82,37 +80,37 @@ const ResolverError = exports.ResolverError = class ResolverError extends JSONPa
       this.ioErrorCode = String(ex.code);
     }
   }
-};
+}
 
 setErrorName(ResolverError);
 
-const UnmatchedResolverError = exports.UnmatchedResolverError = class UnmatchedResolverError extends JSONParserError {
+export class UnmatchedResolverError extends JSONParserError {
   constructor (source) {
     super(`Could not find resolver for "${source}"`, source);
 
     this.code = "EUNMATCHEDRESOLVER";
   }
-};
+}
 
 setErrorName(UnmatchedResolverError);
 
-const MissingPointerError = exports.MissingPointerError = class MissingPointerError extends JSONParserError {
+export class MissingPointerError extends JSONParserError {
   constructor (token, path) {
-    super(`Token "${token}" does not exist.`, stripHash(path));
+    super(`Token "${token}" does not exist.`, url.stripHash(path));
 
     this.code = "EMISSINGPOINTER";
   }
-};
+}
 
 setErrorName(MissingPointerError);
 
-const InvalidPointerError = exports.InvalidPointerError = class InvalidPointerError extends JSONParserError {
+export class InvalidPointerError extends JSONParserError {
   constructor (pointer, path) {
-    super(`Invalid $ref pointer "${pointer}". Pointers must begin with "#/"`, stripHash(path));
+    super(`Invalid $ref pointer "${pointer}". Pointers must begin with "#/"`, url.stripHash(path));
 
     this.code = "EINVALIDPOINTER";
   }
-};
+}
 
 setErrorName(InvalidPointerError);
 
@@ -123,14 +121,14 @@ function setErrorName (err) {
   });
 }
 
-exports.isHandledError = function (err) {
+export function isHandledError (err) {
   return err instanceof JSONParserError || err instanceof JSONParserErrorGroup;
-};
+}
 
-exports.normalizeError = function (err) {
+export function normalizeError (err) {
   if (err.path === null) {
     err.path = [];
   }
 
   return err;
-};
+}
diff --git a/lib/util/plugins.js b/lib/util/plugins.js
index 24d69349..69352b6f 100644
--- a/lib/util/plugins.js
+++ b/lib/util/plugins.js
@@ -1,126 +1,3 @@
-"use strict";
-
-/**
- * Returns the given plugins as an array, rather than an object map.
- * All other methods in this module expect an array of plugins rather than an object map.
- *
- * @param  {object} plugins - A map of plugin objects
- * @return {object[]}
- */
-exports.all = function (plugins) {
-  return Object.keys(plugins)
-    .filter((key) => {
-      return typeof plugins[key] === "object";
-    })
-    .map((key) => {
-      plugins[key].name = key;
-      return plugins[key];
-    });
-};
-
-/**
- * Filters the given plugins, returning only the ones return `true` for the given method.
- *
- * @param  {object[]} plugins - An array of plugin objects
- * @param  {string}   method  - The name of the filter method to invoke for each plugin
- * @param  {object}   file    - A file info object, which will be passed to each method
- * @return {object[]}
- */
-exports.filter = function (plugins, method, file) {
-  return plugins
-    .filter((plugin) => {
-      return !!getResult(plugin, method, file);
-    });
-};
-
-/**
- * Sorts the given plugins, in place, by their `order` property.
- *
- * @param {object[]} plugins - An array of plugin objects
- * @returns {object[]}
- */
-exports.sort = function (plugins) {
-  for (let plugin of plugins) {
-    plugin.order = plugin.order || Number.MAX_SAFE_INTEGER;
-  }
-
-  return plugins.sort((a, b) => { return a.order - b.order; });
-};
-
-/**
- * Runs the specified method of the given plugins, in order, until one of them returns a successful result.
- * Each method can return a synchronous value, a Promise, or call an error-first callback.
- * If the promise resolves successfully, or the callback is called without an error, then the result
- * is immediately returned and no further plugins are called.
- * If the promise rejects, or the callback is called with an error, then the next plugin is called.
- * If ALL plugins fail, then the last error is thrown.
- *
- * @param {object[]}  plugins - An array of plugin objects
- * @param {string}    method  - The name of the method to invoke for each plugin
- * @param {object}    file    - A file info object, which will be passed to each method
- * @returns {Promise}
- */
-exports.run = function (plugins, method, file, $refs) {
-  let plugin, lastError, index = 0;
-
-  return new Promise(((resolve, reject) => {
-    runNextPlugin();
-
-    function runNextPlugin () {
-      plugin = plugins[index++];
-      if (!plugin) {
-        // There are no more functions, so re-throw the last error
-        return reject(lastError);
-      }
-
-      try {
-        // console.log('  %s', plugin.name);
-        let result = getResult(plugin, method, file, callback, $refs);
-        if (result && typeof result.then === "function") {
-          // A promise was returned
-          result.then(onSuccess, onError);
-        }
-        else if (result !== undefined) {
-          // A synchronous result was returned
-          onSuccess(result);
-        }
-        else if (index === plugins.length) {
-          throw new Error("No promise has been returned or callback has been called.");
-        }
-      }
-      catch (e) {
-        onError(e);
-      }
-    }
-
-    function callback (err, result) {
-      if (err) {
-        onError(err);
-      }
-      else {
-        onSuccess(result);
-      }
-    }
-
-    function onSuccess (result) {
-      // console.log('    success');
-      resolve({
-        plugin,
-        result
-      });
-    }
-
-    function onError (error) {
-      // console.log('    %s', err.message || err);
-      lastError = {
-        plugin,
-        error,
-      };
-      runNextPlugin();
-    }
-  }));
-};
-
 /**
  * Returns the value of the given property.
  * If the property is a function, then the result of the function is returned.
@@ -157,3 +34,126 @@ function getResult (obj, prop, file, callback, $refs) {
 
   return value;
 }
+
+export default {
+  /**
+   * Returns the given plugins as an array, rather than an object map.
+   * All other methods in this module expect an array of plugins rather than an object map.
+   *
+   * @param  {object} plugins - A map of plugin objects
+   * @return {object[]}
+   */
+  all (plugins) {
+    return Object.keys(plugins)
+      .filter((key) => {
+        return typeof plugins[key] === "object";
+      })
+      .map((key) => {
+        plugins[key].name = key;
+        return plugins[key];
+      });
+  },
+
+  /**
+   * Filters the given plugins, returning only the ones return `true` for the given method.
+   *
+   * @param  {object[]} plugins - An array of plugin objects
+   * @param  {string}   method  - The name of the filter method to invoke for each plugin
+   * @param  {object}   file    - A file info object, which will be passed to each method
+   * @return {object[]}
+   */
+  filter (plugins, method, file) {
+    return plugins
+      .filter((plugin) => {
+        return !!getResult(plugin, method, file);
+      });
+  },
+
+  /**
+   * Sorts the given plugins, in place, by their `order` property.
+   *
+   * @param {object[]} plugins - An array of plugin objects
+   * @returns {object[]}
+   */
+  sort (plugins) {
+    for (let plugin of plugins) {
+      plugin.order = plugin.order || Number.MAX_SAFE_INTEGER;
+    }
+
+    return plugins.sort((a, b) => { return a.order - b.order; });
+  },
+
+  /**
+   * Runs the specified method of the given plugins, in order, until one of them returns a successful result.
+   * Each method can return a synchronous value, a Promise, or call an error-first callback.
+   * If the promise resolves successfully, or the callback is called without an error, then the result
+   * is immediately returned and no further plugins are called.
+   * If the promise rejects, or the callback is called with an error, then the next plugin is called.
+   * If ALL plugins fail, then the last error is thrown.
+   *
+   * @param {object[]}  plugins - An array of plugin objects
+   * @param {string}    method  - The name of the method to invoke for each plugin
+   * @param {object}    file    - A file info object, which will be passed to each method
+   * @returns {Promise}
+   */
+  run (plugins, method, file, $refs) {
+    let plugin, lastError, index = 0;
+
+    return new Promise(((resolve, reject) => {
+      runNextPlugin();
+
+      function runNextPlugin () {
+        plugin = plugins[index++];
+        if (!plugin) {
+          // There are no more functions, so re-throw the last error
+          return reject(lastError);
+        }
+
+        try {
+          // console.log('  %s', plugin.name);
+          let result = getResult(plugin, method, file, callback, $refs);
+          if (result && typeof result.then === "function") {
+            // A promise was returned
+            result.then(onSuccess, onError);
+          }
+          else if (result !== undefined) {
+            // A synchronous result was returned
+            onSuccess(result);
+          }
+          else if (index === plugins.length) {
+            throw new Error("No promise has been returned or callback has been called.");
+          }
+        }
+        catch (e) {
+          onError(e);
+        }
+      }
+
+      function callback (err, result) {
+        if (err) {
+          onError(err);
+        }
+        else {
+          onSuccess(result);
+        }
+      }
+
+      function onSuccess (result) {
+        // console.log('    success');
+        resolve({
+          plugin,
+          result
+        });
+      }
+
+      function onError (error) {
+        // console.log('    %s', err.message || err);
+        lastError = {
+          plugin,
+          error,
+        };
+        runNextPlugin();
+      }
+    }));
+  },
+};
diff --git a/lib/util/url.js b/lib/util/url.js
index 81b3a0d7..20e987f3 100644
--- a/lib/util/url.js
+++ b/lib/util/url.js
@@ -1,9 +1,8 @@
-"use strict";
+import { parse, resolve } from "url";
 
 let isWindows = /^win/.test(process.platform),
     forwardSlashPattern = /\//g,
     protocolPattern = /^(\w{2,}):\/\//i,
-    url = module.exports,
     jsonPointerSlash = /~1/g,
     jsonPointerTilde = /~0/g;
 
@@ -22,250 +21,253 @@ let urlDecodePatterns = [
   /\%40/g, "@"
 ];
 
-exports.parse = require("url").parse;
-exports.resolve = require("url").resolve;
+export default {
+  /**
+   * Returns the current working directory (in Node) or the current page URL (in browsers).
+   *
+   * @returns {string}
+   */
+  cwd () {
+    if (process.browser) {
+      return location.href;
+    }
 
-/**
- * Returns the current working directory (in Node) or the current page URL (in browsers).
- *
- * @returns {string}
- */
-exports.cwd = function cwd () {
-  if (process.browser) {
-    return location.href;
-  }
+    let path = process.cwd();
 
-  let path = process.cwd();
+    let lastChar = path.slice(-1);
+    if (lastChar === "/" || lastChar === "\\") {
+      return path;
+    }
+    else {
+      return path + "/";
+    }
+  },
 
-  let lastChar = path.slice(-1);
-  if (lastChar === "/" || lastChar === "\\") {
-    return path;
-  }
-  else {
-    return path + "/";
-  }
-};
+  /**
+   * Returns the protocol of the given URL, or `undefined` if it has no protocol.
+   *
+   * @param   {string} path
+   * @returns {?string}
+   */
+  getProtocol (path) {
+    let match = protocolPattern.exec(path);
+    if (match) {
+      return match[1].toLowerCase();
+    }
+  },
 
-/**
- * Returns the protocol of the given URL, or `undefined` if it has no protocol.
- *
- * @param   {string} path
- * @returns {?string}
- */
-exports.getProtocol = function getProtocol (path) {
-  let match = protocolPattern.exec(path);
-  if (match) {
-    return match[1].toLowerCase();
-  }
-};
+  /**
+   * Returns the lowercased file extension of the given URL,
+   * or an empty string if it has no extension.
+   *
+   * @param   {string} path
+   * @returns {string}
+   */
+  getExtension (path) {
+    let lastDot = path.lastIndexOf(".");
+    if (lastDot >= 0) {
+      return this.stripQuery(path.substr(lastDot).toLowerCase());
+    }
+    return "";
+  },
 
-/**
- * Returns the lowercased file extension of the given URL,
- * or an empty string if it has no extension.
- *
- * @param   {string} path
- * @returns {string}
- */
-exports.getExtension = function getExtension (path) {
-  let lastDot = path.lastIndexOf(".");
-  if (lastDot >= 0) {
-    return url.stripQuery(path.substr(lastDot).toLowerCase());
-  }
-  return "";
-};
+  /**
+   * Removes the query, if any, from the given path.
+   *
+   * @param   {string} path
+   * @returns {string}
+   */
+  stripQuery (path) {
+    let queryIndex = path.indexOf("?");
+    if (queryIndex >= 0) {
+      path = path.substr(0, queryIndex);
+    }
+    return path;
+  },
 
-/**
- * Removes the query, if any, from the given path.
- *
- * @param   {string} path
- * @returns {string}
- */
-exports.stripQuery = function stripQuery (path) {
-  let queryIndex = path.indexOf("?");
-  if (queryIndex >= 0) {
-    path = path.substr(0, queryIndex);
-  }
-  return path;
-};
+  /**
+   * Returns the hash (URL fragment), of the given path.
+   * If there is no hash, then the root hash ("#") is returned.
+   *
+   * @param   {string} path
+   * @returns {string}
+   */
+  getHash (path) {
+    let hashIndex = path.indexOf("#");
+    if (hashIndex >= 0) {
+      return path.substr(hashIndex);
+    }
+    return "#";
+  },
 
-/**
- * Returns the hash (URL fragment), of the given path.
- * If there is no hash, then the root hash ("#") is returned.
- *
- * @param   {string} path
- * @returns {string}
- */
-exports.getHash = function getHash (path) {
-  let hashIndex = path.indexOf("#");
-  if (hashIndex >= 0) {
-    return path.substr(hashIndex);
-  }
-  return "#";
-};
+  /**
+   * Removes the hash (URL fragment), if any, from the given path.
+   *
+   * @param   {string} path
+   * @returns {string}
+   */
+  stripHash (path) {
+    let hashIndex = path.indexOf("#");
+    if (hashIndex >= 0) {
+      path = path.substr(0, hashIndex);
+    }
+    return path;
+  },
 
-/**
- * Removes the hash (URL fragment), if any, from the given path.
- *
- * @param   {string} path
- * @returns {string}
- */
-exports.stripHash = function stripHash (path) {
-  let hashIndex = path.indexOf("#");
-  if (hashIndex >= 0) {
-    path = path.substr(0, hashIndex);
-  }
-  return path;
-};
+  /**
+   * Determines whether the given path is an HTTP(S) URL.
+   *
+   * @param   {string} path
+   * @returns {boolean}
+   */
+  isHttp (path) {
+    let protocol = this.getProtocol(path);
+    if (protocol === "http" || protocol === "https") {
+      return true;
+    }
+    else if (protocol === undefined) {
+      // There is no protocol.  If we're running in a browser, then assume it's HTTP.
+      return process.browser;
+    }
+    else {
+      // It's some other protocol, such as "ftp://", "mongodb://", etc.
+      return false;
+    }
+  },
 
-/**
- * Determines whether the given path is an HTTP(S) URL.
- *
- * @param   {string} path
- * @returns {boolean}
- */
-exports.isHttp = function isHttp (path) {
-  let protocol = url.getProtocol(path);
-  if (protocol === "http" || protocol === "https") {
-    return true;
-  }
-  else if (protocol === undefined) {
-    // There is no protocol.  If we're running in a browser, then assume it's HTTP.
-    return process.browser;
-  }
-  else {
-    // It's some other protocol, such as "ftp://", "mongodb://", etc.
-    return false;
-  }
-};
+  /**
+   * Determines whether the given path is a filesystem path.
+   * This includes "file://" URLs.
+   *
+   * @param   {string} path
+   * @returns {boolean}
+   */
+  isFileSystemPath (path) {
+    if (process.browser) {
+      // We're running in a browser, so assume that all paths are URLs.
+      // This way, even relative paths will be treated as URLs rather than as filesystem paths
+      return false;
+    }
 
-/**
- * Determines whether the given path is a filesystem path.
- * This includes "file://" URLs.
- *
- * @param   {string} path
- * @returns {boolean}
- */
-exports.isFileSystemPath = function isFileSystemPath (path) {
-  if (process.browser) {
-    // We're running in a browser, so assume that all paths are URLs.
-    // This way, even relative paths will be treated as URLs rather than as filesystem paths
-    return false;
-  }
+    let protocol = this.getProtocol(path);
+    return protocol === undefined || protocol === "file";
+  },
 
-  let protocol = url.getProtocol(path);
-  return protocol === undefined || protocol === "file";
-};
+  /**
+   * Converts a filesystem path to a properly-encoded URL.
+   *
+   * This is intended to handle situations where JSON Schema $Ref Parser is called
+   * with a filesystem path that contains characters which are not allowed in URLs.
+   *
+   * @example
+   * The following filesystem paths would be converted to the following URLs:
+   *
+   *    <"!@#$%^&*+=?'>.json              ==>   %3C%22!@%23$%25%5E&*+=%3F\'%3E.json
+   *    C:\\My Documents\\File (1).json   ==>   C:/My%20Documents/File%20(1).json
+   *    file://Project #42/file.json      ==>   file://Project%20%2342/file.json
+   *
+   * @param {string} path
+   * @returns {string}
+   */
+  fromFileSystemPath (path) {
+    // Step 1: On Windows, replace backslashes with forward slashes,
+    // rather than encoding them as "%5C"
+    if (isWindows) {
+      path = path.replace(/\\/g, "/");
+    }
 
-/**
- * Converts a filesystem path to a properly-encoded URL.
- *
- * This is intended to handle situations where JSON Schema $Ref Parser is called
- * with a filesystem path that contains characters which are not allowed in URLs.
- *
- * @example
- * The following filesystem paths would be converted to the following URLs:
- *
- *    <"!@#$%^&*+=?'>.json              ==>   %3C%22!@%23$%25%5E&*+=%3F\'%3E.json
- *    C:\\My Documents\\File (1).json   ==>   C:/My%20Documents/File%20(1).json
- *    file://Project #42/file.json      ==>   file://Project%20%2342/file.json
- *
- * @param {string} path
- * @returns {string}
- */
-exports.fromFileSystemPath = function fromFileSystemPath (path) {
-  // Step 1: On Windows, replace backslashes with forward slashes,
-  // rather than encoding them as "%5C"
-  if (isWindows) {
-    path = path.replace(/\\/g, "/");
-  }
+    // Step 2: `encodeURI` will take care of MOST characters
+    path = encodeURI(path);
 
-  // Step 2: `encodeURI` will take care of MOST characters
-  path = encodeURI(path);
+    // Step 3: Manually encode characters that are not encoded by `encodeURI`.
+    // This includes characters such as "#" and "?", which have special meaning in URLs,
+    // but are just normal characters in a filesystem path.
+    for (let i = 0; i < urlEncodePatterns.length; i += 2) {
+      path = path.replace(urlEncodePatterns[i], urlEncodePatterns[i + 1]);
+    }
 
-  // Step 3: Manually encode characters that are not encoded by `encodeURI`.
-  // This includes characters such as "#" and "?", which have special meaning in URLs,
-  // but are just normal characters in a filesystem path.
-  for (let i = 0; i < urlEncodePatterns.length; i += 2) {
-    path = path.replace(urlEncodePatterns[i], urlEncodePatterns[i + 1]);
-  }
+    return path;
+  },
 
-  return path;
-};
+  /**
+   * Converts a URL to a local filesystem path.
+   *
+   * @param {string}  path
+   * @param {boolean} [keepFileProtocol] - If true, then "file://" will NOT be stripped
+   * @returns {string}
+   */
+  toFileSystemPath (path, keepFileProtocol) {
+    // Step 1: `decodeURI` will decode characters such as Cyrillic characters, spaces, etc.
+    path = decodeURI(path);
 
-/**
- * Converts a URL to a local filesystem path.
- *
- * @param {string}  path
- * @param {boolean} [keepFileProtocol] - If true, then "file://" will NOT be stripped
- * @returns {string}
- */
-exports.toFileSystemPath = function toFileSystemPath (path, keepFileProtocol) {
-  // Step 1: `decodeURI` will decode characters such as Cyrillic characters, spaces, etc.
-  path = decodeURI(path);
+    // Step 2: Manually decode characters that are not decoded by `decodeURI`.
+    // This includes characters such as "#" and "?", which have special meaning in URLs,
+    // but are just normal characters in a filesystem path.
+    for (let i = 0; i < urlDecodePatterns.length; i += 2) {
+      path = path.replace(urlDecodePatterns[i], urlDecodePatterns[i + 1]);
+    }
 
-  // Step 2: Manually decode characters that are not decoded by `decodeURI`.
-  // This includes characters such as "#" and "?", which have special meaning in URLs,
-  // but are just normal characters in a filesystem path.
-  for (let i = 0; i < urlDecodePatterns.length; i += 2) {
-    path = path.replace(urlDecodePatterns[i], urlDecodePatterns[i + 1]);
-  }
+    // Step 3: If it's a "file://" URL, then format it consistently
+    // or convert it to a local filesystem path
+    let isFileUrl = path.substr(0, 7).toLowerCase() === "file://";
+    if (isFileUrl) {
+      // Strip-off the protocol, and the initial "/", if there is one
+      path = path[7] === "/" ? path.substr(8) : path.substr(7);
 
-  // Step 3: If it's a "file://" URL, then format it consistently
-  // or convert it to a local filesystem path
-  let isFileUrl = path.substr(0, 7).toLowerCase() === "file://";
-  if (isFileUrl) {
-    // Strip-off the protocol, and the initial "/", if there is one
-    path = path[7] === "/" ? path.substr(8) : path.substr(7);
+      // insert a colon (":") after the drive letter on Windows
+      if (isWindows && path[1] === "/") {
+        path = path[0] + ":" + path.substr(1);
+      }
 
-    // insert a colon (":") after the drive letter on Windows
-    if (isWindows && path[1] === "/") {
-      path = path[0] + ":" + path.substr(1);
+      if (keepFileProtocol) {
+        // Return the consistently-formatted "file://" URL
+        path = "file:///" + path;
+      }
+      else {
+        // Convert the "file://" URL to a local filesystem path.
+        // On Windows, it will start with something like "C:/".
+        // On Posix, it will start with "/"
+        isFileUrl = false;
+        path = isWindows ? path : "/" + path;
+      }
     }
 
-    if (keepFileProtocol) {
-      // Return the consistently-formatted "file://" URL
-      path = "file:///" + path;
-    }
-    else {
-      // Convert the "file://" URL to a local filesystem path.
-      // On Windows, it will start with something like "C:/".
-      // On Posix, it will start with "/"
-      isFileUrl = false;
-      path = isWindows ? path : "/" + path;
+    // Step 4: Normalize Windows paths (unless it's a "file://" URL)
+    if (isWindows && !isFileUrl) {
+      // Replace forward slashes with backslashes
+      path = path.replace(forwardSlashPattern, "\\");
+
+      // Capitalize the drive letter
+      if (path.substr(1, 2) === ":\\") {
+        path = path[0].toUpperCase() + path.substr(1);
+      }
     }
-  }
 
-  // Step 4: Normalize Windows paths (unless it's a "file://" URL)
-  if (isWindows && !isFileUrl) {
-    // Replace forward slashes with backslashes
-    path = path.replace(forwardSlashPattern, "\\");
+    return path;
+  },
 
-    // Capitalize the drive letter
-    if (path.substr(1, 2) === ":\\") {
-      path = path[0].toUpperCase() + path.substr(1);
+  /**
+   * Converts a $ref pointer to a valid JSON Path.
+   *
+   * @param {string}  pointer
+   * @returns {Array<number | string>}
+   */
+  safePointerToPath (pointer) {
+    if (pointer.length <= 1 || pointer[0] !== "#" || pointer[1] !== "/") {
+      return [];
     }
-  }
 
-  return path;
-};
+    return pointer
+      .slice(2)
+      .split("/")
+      .map((value) => {
+        return decodeURIComponent(value)
+          .replace(jsonPointerSlash, "/")
+          .replace(jsonPointerTilde, "~");
+      });
+  },
 
-/**
- * Converts a $ref pointer to a valid JSON Path.
- *
- * @param {string}  pointer
- * @returns {Array<number | string>}
- */
-exports.safePointerToPath = function safePointerToPath (pointer) {
-  if (pointer.length <= 1 || pointer[0] !== "#" || pointer[1] !== "/") {
-    return [];
-  }
+  parse,
 
-  return pointer
-    .slice(2)
-    .split("/")
-    .map((value) => {
-      return decodeURIComponent(value)
-        .replace(jsonPointerSlash, "/")
-        .replace(jsonPointerTilde, "~");
-    });
+  resolve,
 };
diff --git a/package.json b/package.json
index 4cea85a6..129b469a 100644
--- a/package.json
+++ b/package.json
@@ -40,6 +40,7 @@
   "files": [
     "lib"
   ],
+  "type": "module",
   "scripts": {
     "build": "cp LICENSE *.md dist",
     "clean": "shx rm -rf .nyc_output coverage",
diff --git a/test/fixtures/mocha.js b/test/fixtures/mocha.js
index 2d9625c6..5e758542 100644
--- a/test/fixtures/mocha.js
+++ b/test/fixtures/mocha.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { host } = require("@jsdevtools/host-environment");
 
 // Mocha configuration
diff --git a/test/fixtures/polyfill.js b/test/fixtures/polyfill.js
index 7add5abd..1ce493d8 100644
--- a/test/fixtures/polyfill.js
+++ b/test/fixtures/polyfill.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { host } = require("@jsdevtools/host-environment");
 
 // Load the Babel Polyfills for old browsers.
diff --git a/test/specs/__({[ % & $ # @ ` ~ ,)}]__/dereferenced.js b/test/specs/__({[ % & $ # @ ` ~ ,)}]__/dereferenced.js
index c011e237..01011242 100644
--- a/test/specs/__({[ % & $ # @ ` ~ ,)}]__/dereferenced.js	
+++ b/test/specs/__({[ % & $ # @ ` ~ ,)}]__/dereferenced.js	
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   definitions: {
diff --git a/test/specs/__({[ % & $ # @ ` ~ ,)}]__/parsed.js b/test/specs/__({[ % & $ # @ ` ~ ,)}]__/parsed.js
index 61153c01..eedaede1 100644
--- a/test/specs/__({[ % & $ # @ ` ~ ,)}]__/parsed.js	
+++ b/test/specs/__({[ % & $ # @ ` ~ ,)}]__/parsed.js	
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/__({[ % & $ # @ ` ~ ,)}]__/special-characters.spec.js b/test/specs/__({[ % & $ # @ ` ~ ,)}]__/special-characters.spec.js
index cf5f83c6..643d807b 100644
--- a/test/specs/__({[ % & $ # @ ` ~ ,)}]__/special-characters.spec.js	
+++ b/test/specs/__({[ % & $ # @ ` ~ ,)}]__/special-characters.spec.js	
@@ -1,5 +1,3 @@
-"use strict";
-
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
 const path = require("../../utils/path");
diff --git a/test/specs/absolute-root/absolute-root.spec.js b/test/specs/absolute-root/absolute-root.spec.js
index 45541690..9589ac5b 100644
--- a/test/specs/absolute-root/absolute-root.spec.js
+++ b/test/specs/absolute-root/absolute-root.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const { resolve } = require("path");
 const $RefParser = require("../../..");
diff --git a/test/specs/absolute-root/bundled.js b/test/specs/absolute-root/bundled.js
index db7919ec..635d392a 100644
--- a/test/specs/absolute-root/bundled.js
+++ b/test/specs/absolute-root/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/absolute-root/dereferenced.js b/test/specs/absolute-root/dereferenced.js
index d82f1ca5..3d0e2c30 100644
--- a/test/specs/absolute-root/dereferenced.js
+++ b/test/specs/absolute-root/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/absolute-root/parsed.js b/test/specs/absolute-root/parsed.js
index d6c1349f..f3aaf050 100644
--- a/test/specs/absolute-root/parsed.js
+++ b/test/specs/absolute-root/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/blank/blank.spec.js b/test/specs/blank/blank.spec.js
index a8f59a14..1ef6bc92 100644
--- a/test/specs/blank/blank.spec.js
+++ b/test/specs/blank/blank.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { host } = require("@jsdevtools/host-environment");
 const { expect } = require("chai");
 const $RefParser = require("../../..");
diff --git a/test/specs/blank/dereferenced.js b/test/specs/blank/dereferenced.js
index 6dc06e5c..10986093 100644
--- a/test/specs/blank/dereferenced.js
+++ b/test/specs/blank/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports = {
   json: undefined,
   yaml: undefined,
diff --git a/test/specs/blank/parsed.js b/test/specs/blank/parsed.js
index d55e6748..523c5638 100644
--- a/test/specs/blank/parsed.js
+++ b/test/specs/blank/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/callbacks.spec.js b/test/specs/callbacks.spec.js
index ecd43ebb..3b9a24f2 100644
--- a/test/specs/callbacks.spec.js
+++ b/test/specs/callbacks.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../lib");
 const helper = require("../utils/helper");
diff --git a/test/specs/circular-extended/bundled.js b/test/specs/circular-extended/bundled.js
index 77352209..e3988e85 100644
--- a/test/specs/circular-extended/bundled.js
+++ b/test/specs/circular-extended/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const bundledSchema = module.exports =
 {
   self: {
diff --git a/test/specs/circular-extended/circular-extended.spec.js b/test/specs/circular-extended/circular-extended.spec.js
index 14d8fd12..8827b31e 100644
--- a/test/specs/circular-extended/circular-extended.spec.js
+++ b/test/specs/circular-extended/circular-extended.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/circular-extended/dereferenced.js b/test/specs/circular-extended/dereferenced.js
index 527b1a75..97c7f767 100644
--- a/test/specs/circular-extended/dereferenced.js
+++ b/test/specs/circular-extended/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const dereferencedSchema = module.exports =
 {
   self: {
diff --git a/test/specs/circular-extended/parsed.js b/test/specs/circular-extended/parsed.js
index e9054c2c..a44602d9 100644
--- a/test/specs/circular-extended/parsed.js
+++ b/test/specs/circular-extended/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   self: {
diff --git a/test/specs/circular-external-direct/circular-external-direct.spec.js b/test/specs/circular-external-direct/circular-external-direct.spec.js
index 408ec73f..bdbb1490 100644
--- a/test/specs/circular-external-direct/circular-external-direct.spec.js
+++ b/test/specs/circular-external-direct/circular-external-direct.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const chai = require("chai");
 const chaiSubset = require("chai-subset");
 chai.use(chaiSubset);
diff --git a/test/specs/circular-external-direct/dereferenced.js b/test/specs/circular-external-direct/dereferenced.js
index 30ac5ddc..3565623b 100644
--- a/test/specs/circular-external-direct/dereferenced.js
+++ b/test/specs/circular-external-direct/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
   {
     $ref: "./circular-external-direct-root.yaml#/foo",
diff --git a/test/specs/circular-external-direct/parsed.js b/test/specs/circular-external-direct/parsed.js
index 8ffbbd6e..67be0e20 100644
--- a/test/specs/circular-external-direct/parsed.js
+++ b/test/specs/circular-external-direct/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/circular-external/bundled.js b/test/specs/circular-external/bundled.js
index 39ec2ca9..e7b31b03 100644
--- a/test/specs/circular-external/bundled.js
+++ b/test/specs/circular-external/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   definitions: {
diff --git a/test/specs/circular-external/circular-external.spec.js b/test/specs/circular-external/circular-external.spec.js
index bf60c30f..3b29b1fd 100644
--- a/test/specs/circular-external/circular-external.spec.js
+++ b/test/specs/circular-external/circular-external.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/circular-external/dereferenced.js b/test/specs/circular-external/dereferenced.js
index 5d952c5d..6d3f9e9b 100644
--- a/test/specs/circular-external/dereferenced.js
+++ b/test/specs/circular-external/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const dereferencedSchema = module.exports =
 {
   definitions: {
diff --git a/test/specs/circular-external/parsed.js b/test/specs/circular-external/parsed.js
index b9367703..65c75080 100644
--- a/test/specs/circular-external/parsed.js
+++ b/test/specs/circular-external/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/circular-multi/bundled.js b/test/specs/circular-multi/bundled.js
index 780ce18d..e6dcd535 100644
--- a/test/specs/circular-multi/bundled.js
+++ b/test/specs/circular-multi/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports = {
   $schema: "http://json-schema.org/draft-07/schema#",
   properties: {
diff --git a/test/specs/circular-multi/circular-multi.spec.js b/test/specs/circular-multi/circular-multi.spec.js
index f7889693..222b56ae 100644
--- a/test/specs/circular-multi/circular-multi.spec.js
+++ b/test/specs/circular-multi/circular-multi.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const path = require("../../utils/path");
diff --git a/test/specs/circular/circular.spec.js b/test/specs/circular/circular.spec.js
index 2ba5b886..54001ca9 100644
--- a/test/specs/circular/circular.spec.js
+++ b/test/specs/circular/circular.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/circular/dereferenced.js b/test/specs/circular/dereferenced.js
index 519893dc..3cff0449 100644
--- a/test/specs/circular/dereferenced.js
+++ b/test/specs/circular/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const dereferencedSchema = module.exports =
 {
   self: {
diff --git a/test/specs/circular/parsed.js b/test/specs/circular/parsed.js
index fff22719..e118905c 100644
--- a/test/specs/circular/parsed.js
+++ b/test/specs/circular/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   self: {
diff --git a/test/specs/date-strings/date-strings.spec.js b/test/specs/date-strings/date-strings.spec.js
index 7de4acce..4f0a4754 100644
--- a/test/specs/date-strings/date-strings.spec.js
+++ b/test/specs/date-strings/date-strings.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/date-strings/parsed.js b/test/specs/date-strings/parsed.js
index c9228a93..4963049e 100644
--- a/test/specs/date-strings/parsed.js
+++ b/test/specs/date-strings/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports = {
   schema: {
     title: "Date Strings",
diff --git a/test/specs/deep-circular/bundled.js b/test/specs/deep-circular/bundled.js
index d1ba471d..f9fc6b66 100644
--- a/test/specs/deep-circular/bundled.js
+++ b/test/specs/deep-circular/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Deep Schema",
diff --git a/test/specs/deep-circular/deep-circular.spec.js b/test/specs/deep-circular/deep-circular.spec.js
index 00ae32bb..87e6e0da 100644
--- a/test/specs/deep-circular/deep-circular.spec.js
+++ b/test/specs/deep-circular/deep-circular.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/deep-circular/dereferenced.js b/test/specs/deep-circular/dereferenced.js
index 1da07d24..8d8a200e 100644
--- a/test/specs/deep-circular/dereferenced.js
+++ b/test/specs/deep-circular/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 let name = {
   required: [
     "first",
diff --git a/test/specs/deep-circular/parsed.js b/test/specs/deep-circular/parsed.js
index 7c4d7186..c8063db5 100644
--- a/test/specs/deep-circular/parsed.js
+++ b/test/specs/deep-circular/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/deep/bundled.js b/test/specs/deep/bundled.js
index b47d6922..330f1076 100644
--- a/test/specs/deep/bundled.js
+++ b/test/specs/deep/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   type: "object",
diff --git a/test/specs/deep/deep.spec.js b/test/specs/deep/deep.spec.js
index 30d9ac60..f2a0ab2e 100644
--- a/test/specs/deep/deep.spec.js
+++ b/test/specs/deep/deep.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/deep/dereferenced.js b/test/specs/deep/dereferenced.js
index 59035087..0b3f02e2 100644
--- a/test/specs/deep/dereferenced.js
+++ b/test/specs/deep/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 let name = {
   required: [
     "first",
diff --git a/test/specs/deep/parsed.js b/test/specs/deep/parsed.js
index 24218bb2..06d43d02 100644
--- a/test/specs/deep/parsed.js
+++ b/test/specs/deep/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/empty/empty.spec.js b/test/specs/empty/empty.spec.js
index f3815726..999a870e 100644
--- a/test/specs/empty/empty.spec.js
+++ b/test/specs/empty/empty.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../../lib");
 const helper = require("../../utils/helper");
diff --git a/test/specs/error-source/error-source.spec.js b/test/specs/error-source/error-source.spec.js
index 4315c8bf..30c05497 100644
--- a/test/specs/error-source/error-source.spec.js
+++ b/test/specs/error-source/error-source.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const chai = require("chai");
 const chaiSubset = require("chai-subset");
 chai.use(chaiSubset);
diff --git a/test/specs/exports.spec.js b/test/specs/exports.spec.js
index 1c87693d..0a3c096d 100644
--- a/test/specs/exports.spec.js
+++ b/test/specs/exports.spec.js
@@ -1,6 +1,4 @@
 /* eslint-disable require-await */
-"use strict";
-
 const { expect } = require("chai");
 const commonJSExport = require("../../");
 const { default: defaultExport } = require("../../");
diff --git a/test/specs/external-from-internal/bundled.js b/test/specs/external-from-internal/bundled.js
index 9b8caa3e..a3bce65a 100644
--- a/test/specs/external-from-internal/bundled.js
+++ b/test/specs/external-from-internal/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports = {
   internal1: {
     $ref: "#/external1"
diff --git a/test/specs/external-from-internal/dereferenced.js b/test/specs/external-from-internal/dereferenced.js
index edf7d382..adddf134 100644
--- a/test/specs/external-from-internal/dereferenced.js
+++ b/test/specs/external-from-internal/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   internal1: {
diff --git a/test/specs/external-from-internal/external-from-internal.spec.js b/test/specs/external-from-internal/external-from-internal.spec.js
index 75a36d22..b3d830ee 100644
--- a/test/specs/external-from-internal/external-from-internal.spec.js
+++ b/test/specs/external-from-internal/external-from-internal.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/external-from-internal/parsed.js b/test/specs/external-from-internal/parsed.js
index f4553079..657a66ad 100644
--- a/test/specs/external-from-internal/parsed.js
+++ b/test/specs/external-from-internal/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/external-multiple/bundled.js b/test/specs/external-multiple/bundled.js
index 782dd3dd..bc84683d 100644
--- a/test/specs/external-multiple/bundled.js
+++ b/test/specs/external-multiple/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports = {
   type: "object",
   required: ["user", "token"],
diff --git a/test/specs/external-multiple/dereferenced.js b/test/specs/external-multiple/dereferenced.js
index d2bcf464..eb4e9052 100644
--- a/test/specs/external-multiple/dereferenced.js
+++ b/test/specs/external-multiple/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports = {
   type: "object",
   required: ["user", "token"],
diff --git a/test/specs/external-multiple/external-multiple.spec.js b/test/specs/external-multiple/external-multiple.spec.js
index bbefe176..9cefc0cd 100644
--- a/test/specs/external-multiple/external-multiple.spec.js
+++ b/test/specs/external-multiple/external-multiple.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/external-multiple/parsed.js b/test/specs/external-multiple/parsed.js
index 29bafd16..38350713 100644
--- a/test/specs/external-multiple/parsed.js
+++ b/test/specs/external-multiple/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports = {
   schema: {
     type: "object",
diff --git a/test/specs/external-partial/bundled.js b/test/specs/external-partial/bundled.js
index 93e97832..92b4cd21 100644
--- a/test/specs/external-partial/bundled.js
+++ b/test/specs/external-partial/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/external-partial/dereferenced.js b/test/specs/external-partial/dereferenced.js
index e56ea468..fd593769 100644
--- a/test/specs/external-partial/dereferenced.js
+++ b/test/specs/external-partial/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/external-partial/external-partial.spec.js b/test/specs/external-partial/external-partial.spec.js
index 2ab233b4..d35ab92a 100644
--- a/test/specs/external-partial/external-partial.spec.js
+++ b/test/specs/external-partial/external-partial.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/external-partial/parsed.js b/test/specs/external-partial/parsed.js
index e3043c06..dd475524 100644
--- a/test/specs/external-partial/parsed.js
+++ b/test/specs/external-partial/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/external/bundled.js b/test/specs/external/bundled.js
index db7919ec..635d392a 100644
--- a/test/specs/external/bundled.js
+++ b/test/specs/external/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/external/dereferenced.js b/test/specs/external/dereferenced.js
index d82f1ca5..3d0e2c30 100644
--- a/test/specs/external/dereferenced.js
+++ b/test/specs/external/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/external/external.spec.js b/test/specs/external/external.spec.js
index f1a8ec4b..78e28e3c 100644
--- a/test/specs/external/external.spec.js
+++ b/test/specs/external/external.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/external/parsed.js b/test/specs/external/parsed.js
index d6c1349f..f3aaf050 100644
--- a/test/specs/external/parsed.js
+++ b/test/specs/external/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/http.spec.js b/test/specs/http.spec.js
index 9cd2add4..ac296556 100644
--- a/test/specs/http.spec.js
+++ b/test/specs/http.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { host } = require("@jsdevtools/host-environment");
 const { expect } = require("chai");
 const $RefParser = require("../../lib");
diff --git a/test/specs/internal/bundled.js b/test/specs/internal/bundled.js
index dc923eec..af9f0b24 100644
--- a/test/specs/internal/bundled.js
+++ b/test/specs/internal/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   definitions: {
diff --git a/test/specs/internal/dereferenced.js b/test/specs/internal/dereferenced.js
index 1e971e0d..f3524ffe 100644
--- a/test/specs/internal/dereferenced.js
+++ b/test/specs/internal/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   definitions: {
diff --git a/test/specs/internal/internal.spec.js b/test/specs/internal/internal.spec.js
index f43875e5..0a07b4b5 100644
--- a/test/specs/internal/internal.spec.js
+++ b/test/specs/internal/internal.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/internal/parsed.js b/test/specs/internal/parsed.js
index b9bf16a6..ed84fe03 100644
--- a/test/specs/internal/parsed.js
+++ b/test/specs/internal/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   definitions: {
diff --git a/test/specs/invalid-pointers/invalid-pointers.js b/test/specs/invalid-pointers/invalid-pointers.js
index bc62d936..f20224fa 100644
--- a/test/specs/invalid-pointers/invalid-pointers.js
+++ b/test/specs/invalid-pointers/invalid-pointers.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const chai = require("chai");
 const chaiSubset = require("chai-subset");
 chai.use(chaiSubset);
diff --git a/test/specs/invalid/invalid.spec.js b/test/specs/invalid/invalid.spec.js
index dc6db7f9..603fb42d 100644
--- a/test/specs/invalid/invalid.spec.js
+++ b/test/specs/invalid/invalid.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { host } = require("@jsdevtools/host-environment");
 const chai = require("chai");
 const chaiSubset = require("chai-subset");
diff --git a/test/specs/missing-pointers/missing-pointers.spec.js b/test/specs/missing-pointers/missing-pointers.spec.js
index 4270bee9..7418bf75 100644
--- a/test/specs/missing-pointers/missing-pointers.spec.js
+++ b/test/specs/missing-pointers/missing-pointers.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const chai = require("chai");
 const chaiSubset = require("chai-subset");
 chai.use(chaiSubset);
diff --git a/test/specs/no-refs/no-refs.spec.js b/test/specs/no-refs/no-refs.spec.js
index fe87615e..aa374523 100644
--- a/test/specs/no-refs/no-refs.spec.js
+++ b/test/specs/no-refs/no-refs.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/no-refs/parsed.js b/test/specs/no-refs/parsed.js
index 2cadce72..bcdc5a6c 100644
--- a/test/specs/no-refs/parsed.js
+++ b/test/specs/no-refs/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   required: [
diff --git a/test/specs/object-source-with-path/bundled.js b/test/specs/object-source-with-path/bundled.js
index 7a2e5898..dc0addc8 100644
--- a/test/specs/object-source-with-path/bundled.js
+++ b/test/specs/object-source-with-path/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/object-source-with-path/dereferenced.js b/test/specs/object-source-with-path/dereferenced.js
index e5a5eb39..ea5a9d81 100644
--- a/test/specs/object-source-with-path/dereferenced.js
+++ b/test/specs/object-source-with-path/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/object-source-with-path/object-source-with-path.spec.js b/test/specs/object-source-with-path/object-source-with-path.spec.js
index 5393f8b1..5caa9211 100644
--- a/test/specs/object-source-with-path/object-source-with-path.spec.js
+++ b/test/specs/object-source-with-path/object-source-with-path.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/object-source-with-path/parsed.js b/test/specs/object-source-with-path/parsed.js
index a12db7e7..152104e8 100644
--- a/test/specs/object-source-with-path/parsed.js
+++ b/test/specs/object-source-with-path/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/object-source/bundled.js b/test/specs/object-source/bundled.js
index 7a2e5898..dc0addc8 100644
--- a/test/specs/object-source/bundled.js
+++ b/test/specs/object-source/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/object-source/dereferenced.js b/test/specs/object-source/dereferenced.js
index e5a5eb39..ea5a9d81 100644
--- a/test/specs/object-source/dereferenced.js
+++ b/test/specs/object-source/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/object-source/object-source.spec.js b/test/specs/object-source/object-source.spec.js
index 57c294ce..223b98a6 100644
--- a/test/specs/object-source/object-source.spec.js
+++ b/test/specs/object-source/object-source.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/object-source/parsed.js b/test/specs/object-source/parsed.js
index fe034a4f..9f6fa301 100644
--- a/test/specs/object-source/parsed.js
+++ b/test/specs/object-source/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const path = require("../../utils/path");
 
 module.exports =
diff --git a/test/specs/parsers/dereferenced.js b/test/specs/parsers/dereferenced.js
index 0d7e4997..2e8b6695 100644
--- a/test/specs/parsers/dereferenced.js
+++ b/test/specs/parsers/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports = {
   defaultParsers: {
     definitions: {
diff --git a/test/specs/parsers/parsed.js b/test/specs/parsers/parsed.js
index 8dc803ab..e425405c 100644
--- a/test/specs/parsers/parsed.js
+++ b/test/specs/parsers/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/parsers/parsers.spec.js b/test/specs/parsers/parsers.spec.js
index 506d1cf7..2c4b15e5 100644
--- a/test/specs/parsers/parsers.spec.js
+++ b/test/specs/parsers/parsers.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const chai = require("chai");
 const chaiSubset = require("chai-subset");
 chai.use(chaiSubset);
diff --git a/test/specs/ref-in-excluded-path/dereferenced.js b/test/specs/ref-in-excluded-path/dereferenced.js
index bd995c99..885e287d 100644
--- a/test/specs/ref-in-excluded-path/dereferenced.js
+++ b/test/specs/ref-in-excluded-path/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports = {
   components: {
     examples: {
diff --git a/test/specs/ref-in-excluded-path/ref-in-excluded-path.spec.js b/test/specs/ref-in-excluded-path/ref-in-excluded-path.spec.js
index a462932e..8499e692 100644
--- a/test/specs/ref-in-excluded-path/ref-in-excluded-path.spec.js
+++ b/test/specs/ref-in-excluded-path/ref-in-excluded-path.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const path = require("../../utils/path");
diff --git a/test/specs/refs.spec.js b/test/specs/refs.spec.js
index be9bbdc9..55e706df 100644
--- a/test/specs/refs.spec.js
+++ b/test/specs/refs.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { host } = require("@jsdevtools/host-environment");
 const { expect } = require("chai");
 const $RefParser = require("../../lib");
diff --git a/test/specs/resolvers/dereferenced.js b/test/specs/resolvers/dereferenced.js
index fae7aace..81474b65 100644
--- a/test/specs/resolvers/dereferenced.js
+++ b/test/specs/resolvers/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   definitions: {
diff --git a/test/specs/resolvers/parsed.js b/test/specs/resolvers/parsed.js
index 25fd633a..07a58f67 100644
--- a/test/specs/resolvers/parsed.js
+++ b/test/specs/resolvers/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   definitions: {
diff --git a/test/specs/resolvers/resolvers.spec.js b/test/specs/resolvers/resolvers.spec.js
index 3dd95144..36dfe4d0 100644
--- a/test/specs/resolvers/resolvers.spec.js
+++ b/test/specs/resolvers/resolvers.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const chai = require("chai");
 const chaiSubset = require("chai-subset");
 chai.use(chaiSubset);
diff --git a/test/specs/root/bundled.js b/test/specs/root/bundled.js
index c16becab..d87f6766 100644
--- a/test/specs/root/bundled.js
+++ b/test/specs/root/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Extending a root $ref",
diff --git a/test/specs/root/dereferenced.js b/test/specs/root/dereferenced.js
index c16becab..d87f6766 100644
--- a/test/specs/root/dereferenced.js
+++ b/test/specs/root/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Extending a root $ref",
diff --git a/test/specs/root/parsed.js b/test/specs/root/parsed.js
index 3fcce63c..6a369422 100644
--- a/test/specs/root/parsed.js
+++ b/test/specs/root/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/root/root.spec.js b/test/specs/root/root.spec.js
index e15cb31c..34f45da1 100644
--- a/test/specs/root/root.spec.js
+++ b/test/specs/root/root.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/substrings/bundled.js b/test/specs/substrings/bundled.js
index 96dc4c0e..2066cf10 100644
--- a/test/specs/substrings/bundled.js
+++ b/test/specs/substrings/bundled.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/substrings/dereferenced.js b/test/specs/substrings/dereferenced.js
index e79bfaa8..5bbabf82 100644
--- a/test/specs/substrings/dereferenced.js
+++ b/test/specs/substrings/dereferenced.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   title: "Person",
diff --git a/test/specs/substrings/parsed.js b/test/specs/substrings/parsed.js
index bdfb3419..41cd00f2 100644
--- a/test/specs/substrings/parsed.js
+++ b/test/specs/substrings/parsed.js
@@ -1,5 +1,3 @@
-"use strict";
-
 module.exports =
 {
   schema: {
diff --git a/test/specs/substrings/substrings.spec.js b/test/specs/substrings/substrings.spec.js
index ea7b3437..dae5ab52 100644
--- a/test/specs/substrings/substrings.spec.js
+++ b/test/specs/substrings/substrings.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { expect } = require("chai");
 const $RefParser = require("../../..");
 const helper = require("../../utils/helper");
diff --git a/test/specs/util/url.spec.js b/test/specs/util/url.spec.js
index b0b464c9..7bfd4660 100644
--- a/test/specs/util/url.spec.js
+++ b/test/specs/util/url.spec.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const chai = require("chai");
 const chaiSubset = require("chai-subset");
 chai.use(chaiSubset);
diff --git a/test/utils/helper.js b/test/utils/helper.js
index e201bf64..03127f3d 100644
--- a/test/utils/helper.js
+++ b/test/utils/helper.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const $RefParser = require("../../lib");
 const { host } = require("@jsdevtools/host-environment");
 const { expect } = require("chai");
diff --git a/test/utils/path.js b/test/utils/path.js
index 8f468a84..6b513280 100644
--- a/test/utils/path.js
+++ b/test/utils/path.js
@@ -1,5 +1,3 @@
-"use strict";
-
 const { host } = require("@jsdevtools/host-environment");
 
 if (host.node) {