Declare types for node builtin modules in REPL so you do not need to import them (#1500)

* Declare types for node builtin modules in REPL so you do not need to
import them

* fix

* fix

Author: cspotcode

src/index.ts

@@ -685,6 +685,15 @@ export function create(rawOptions: CreateOptions = {}): Service {
     });
   }
 
+  /**
+   * True if require() hooks should interop with experimental ESM loader.
+   * Enabled explicitly via a flag since it is a breaking change.
+   */
+  let experimentalEsmLoader = false;
+  function enableExperimentalEsmLoaderInterop() {
+    experimentalEsmLoader = true;
+  }
+
   // Install source map support and read from memory cache.
   installSourceMapSupport();
   function installSourceMapSupport() {
@@ -1267,15 +1276,6 @@ export function create(rawOptions: CreateOptions = {}): Service {
     });
   }
 
-  /**
-   * True if require() hooks should interop with experimental ESM loader.
-   * Enabled explicitly via a flag since it is a breaking change.
-   */
-  let experimentalEsmLoader = false;
-  function enableExperimentalEsmLoaderInterop() {
-    experimentalEsmLoader = true;
-  }
-
   return {
     [TS_NODE_SERVICE_BRAND]: true,
     ts,

src/repl.ts

@@ -14,6 +14,7 @@ import { Console } from 'console';
 import * as assert from 'assert';
 import type * as tty from 'tty';
 import type * as Module from 'module';
+import { builtinModules } from 'module';
 
 // Lazy-loaded.
 let _processTopLevelAwait: (src: string) => string | null;
@@ -356,6 +357,22 @@ export function createRepl(options: CreateReplOptions = {}) {
       if (forceToBeModule) {
         state.input += 'export {};void 0;\n';
       }
+
+      // Declare node builtins.
+      // Skip the same builtins as `addBuiltinLibsToObject`:
+      //   those starting with _
+      //   those containing /
+      //   those that already exist as globals
+      // Intentionally suppress type errors in case @types/node does not declare any of them.
+      state.input += `// @ts-ignore\n${builtinModules
+        .filter(
+          (name) =>
+            !name.startsWith('_') &&
+            !name.includes('/') &&
+            !['console', 'module', 'process'].includes(name)
+        )
+        .map((name) => `declare import ${name} = require('${name}')`)
+        .join(';')}\n`;
     }
 
     reset();

src/test/helpers.ts

@@ -40,6 +40,8 @@ export const CMD_ESM_LOADER_WITHOUT_PROJECT = `node ${EXPERIMENTAL_MODULES_FLAG}
 // `createRequire` does not exist on older node versions
 export const testsDirRequire = createRequire(join(TEST_DIR, 'index.js'));
 
+export const ts = testsDirRequire('typescript');
+
 export const xfs = new NodeFS(fs);
 
 /** Pass to `test.context()` to get access to the ts-node API under test */

src/test/index.spec.ts

@@ -3,7 +3,7 @@ import * as expect from 'expect';
 import { join, resolve, sep as pathSep } from 'path';
 import { tmpdir } from 'os';
 import semver = require('semver');
-import ts = require('typescript');
+import { ts } from './helpers';
 import { lstatSync, mkdtempSync } from 'fs';
 import { npath } from '@yarnpkg/fslib';
 import type _createRequire from 'create-require';

src/test/repl/node-repl-tla.ts

@@ -2,7 +2,7 @@ import { expect } from 'chai';
 import type { Key } from 'readline';
 import { Stream } from 'stream';
 import semver = require('semver');
-import ts = require('typescript');
+import { ts } from '../helpers';
 import type { ContextWithTsNodeUnderTest } from './helpers';
 
 interface SharedObjects extends ContextWithTsNodeUnderTest {

src/test/repl/repl-environment.spec.ts

@@ -94,7 +94,7 @@ test.suite(
       }
     );
 
-    const declareGlobals = `declare var replReport: any, stdinReport: any, evalReport: any, restReport: any, global: any, __filename: any, __dirname: any, module: any, exports: any, fs: any;`;
+    const declareGlobals = `declare var replReport: any, stdinReport: any, evalReport: any, restReport: any, global: any, __filename: any, __dirname: any, module: any, exports: any;`;
     function setReportGlobal(type: 'repl' | 'stdin' | 'eval') {
       return `
             ${declareGlobals}
@@ -107,7 +107,7 @@ test.suite(
               modulePaths: typeof module !== 'undefined' && [...module.paths],
               exportsTest: typeof exports !== 'undefined' ? module.exports === exports : null,
               stackTest: new Error().stack!.split('\\n')[1],
-              moduleAccessorsTest: typeof fs === 'undefined' ? null : fs === require('fs'),
+              moduleAccessorsTest: eval('typeof fs') === 'undefined' ? null : eval('fs') === require('fs'),
               argv: [...process.argv]
             };
           `.replace(/\n/g, '');
@@ -203,7 +203,7 @@ test.suite(
           exportsTest: true,
           // Note: vanilla node uses different name. See #1360
           stackTest: expect.stringContaining(
-            `    at ${join(TEST_DIR, '<repl>.ts')}:2:`
+            `    at ${join(TEST_DIR, '<repl>.ts')}:4:`
           ),
           moduleAccessorsTest: true,
           argv: [tsNodeExe],
@@ -356,7 +356,7 @@ test.suite(
           exportsTest: true,
           // Note: vanilla node uses different name. See #1360
           stackTest: expect.stringContaining(
-            `    at ${join(TEST_DIR, '<repl>.ts')}:2:`
+            `    at ${join(TEST_DIR, '<repl>.ts')}:4:`
           ),
           moduleAccessorsTest: true,
           argv: [tsNodeExe],

src/test/repl/repl.spec.ts

@@ -1,4 +1,4 @@
-import ts = require('typescript');
+import { ts } from '../helpers';
 import semver = require('semver');
 import * as expect from 'expect';
 import {
@@ -212,7 +212,7 @@ test.suite('top level await', (_test) => {
 
         expect(stdout).toBe('> > ');
         expect(stderr.replace(/\r\n/g, '\n')).toBe(
-          '<repl>.ts(2,7): error TS2322: ' +
+          '<repl>.ts(4,7): error TS2322: ' +
             (semver.gte(ts.version, '4.0.0')
               ? `Type 'number' is not assignable to type 'string'.\n`
               : `Type '1' is not assignable to type 'string'.\n`) +
@@ -411,3 +411,30 @@ test.suite(
     );
   }
 );
+
+test.serial('REPL declares types for node built-ins within REPL', async (t) => {
+  const { stdout, stderr } = await t.context.executeInRepl(
+    `util.promisify(setTimeout)("should not be a string" as string)
+    type Duplex = stream.Duplex
+    const s = stream
+    'done'`,
+    {
+      registerHooks: true,
+      waitPattern: `done`,
+      startInternalOptions: {
+        useGlobal: false,
+      },
+    }
+  );
+
+  // Assert that we receive a typechecking error about improperly using
+  // `util.promisify` but *not* an error about the absence of `util`
+  expect(stderr).not.toMatch("Cannot find name 'util'");
+  expect(stderr).toMatch(
+    "Argument of type 'string' is not assignable to parameter of type 'number'"
+  );
+  // Assert that both types and values can be used without error
+  expect(stderr).not.toMatch("Cannot find namespace 'stream'");
+  expect(stderr).not.toMatch("Cannot find name 'stream'");
+  expect(stdout).toMatch(`done`);
+});