Add types

.npmrc

@@ -0,0 +1 @@
+package-lock=false

package.json

@@ -19,16 +19,21 @@
   "author": "Eugene Sharygin <[email protected]>",
   "contributors": [
     "Eugene Sharygin <[email protected]>",
-    "Titus Wormer <[email protected]> (https://wooorm.com)"
+    "Titus Wormer <[email protected]> (https://wooorm.com)",
+    "Christian Murphy <[email protected]>"
   ],
   "files": [
-    "index.js"
+    "index.js",
+    "types/index.d.ts"
   ],
+  "types": "types/index.d.ts",
   "dependencies": {
     "flatmap": "0.0.3",
-    "unist-util-is": "^3.0.0"
+    "unist-util-is": "^4.0.0"
   },
   "devDependencies": {
+    "@types/mdast": "^3.0.3",
+    "dtslint": "^0.9.9",
     "nyc": "^14.0.0",
     "prettier": "^1.0.0",
     "remark-cli": "^6.0.0",
@@ -41,7 +46,8 @@
     "format": "remark . -qfo && prettier --write \"**/*.js\" && xo --fix",
     "test-api": "node test",
     "test-coverage": "nyc --reporter lcov tape test.js",
-    "test": "npm run format && npm run test-coverage"
+    "test-types": "dtslint types",
+    "test": "npm run format && npm run test-coverage && npm run test-types"
   },
   "nyc": {
     "check-coverage": true,

types/index.d.ts

@@ -0,0 +1,47 @@
+// TypeScript Version: 3.5
+
+import {Node} from 'unist'
+import {Test} from 'unist-util-is'
+
+declare namespace unistUtilFilter {
+  /**
+   * Options for unist util filter
+   */
+  interface Options {
+    /**
+     * Whether to drop parent nodes if they had children,
+     * but all their children were filtered out
+     *
+     * @default true
+     */
+    cascade?: boolean
+  }
+}
+
+/**
+ * Create a new tree consisting of copies of all nodes that pass test.
+ * The tree is walked in preorder (NLR), visiting the node itself, then its head, etc.
+ *
+ * @param tree Tree to filter
+ * @param filter unist-util-is compatible test
+ */
+declare function unistUtilFilter<T extends Node>(
+  tree: Node,
+  filter?: Test<T>
+): T | null
+
+/**
+ * Create a new tree consisting of copies of all nodes that pass test.
+ * The tree is walked in preorder (NLR), visiting the node itself, then its head, etc.
+ *
+ * @param tree Tree to filter
+ * @param options additional configuration
+ * @param filter unist-util-is compatible test
+ */
+declare function unistUtilFilter<T extends Node>(
+  tree: Node,
+  options: unistUtilFilter.Options,
+  filter?: Test<T>
+): T | null
+
+export = unistUtilFilter

types/tsconfig.json

@@ -0,0 +1,10 @@
+{
+  "compilerOptions": {
+    "lib": ["es2015"],
+    "strict": true,
+    "baseUrl": ".",
+    "paths": {
+      "unist-util-filter": ["index.d.ts"]
+    }
+  }
+}

types/tslint.json

@@ -0,0 +1,8 @@
+{
+  "extends": "dtslint/dtslint.json",
+  "rules": {
+    "whitespace": false,
+    "semicolon": false,
+    "no-redundant-jsdoc": false
+  }
+}

types/unist-util-filter-tests.ts

@@ -0,0 +1,11 @@
+import * as filter from 'unist-util-filter'
+import {Heading} from 'mdast'
+
+filter() // $ExpectError
+filter({type: 'root'}) // $ExpectType Node | null
+filter({type: 'root'}, 'root') // $ExpectType Node | null
+filter({type: 'root'}, {}, 'root') // $ExpectType Node | null
+filter({type: 'root'}, {notAnOption: true}, 'root') // $ExpectError
+filter({type: 'root'}, {cascade: false}, 'root') // $ExpectType Node | null
+filter<Heading>({type: 'root'}, 'heading') // $ExpectType Heading | null
+filter<Heading>({type: 'root'}, 'notAHeading') // $ExpectError