[patch] add types

Author: ljharb

.github/workflows/node-aught.yml

@@ -9,10 +9,11 @@ jobs:
       range: '< 10'
       type: minors
       command: npm run tests-only
+      skip-ls-check: true
 
   node:
     name: 'node < 10'
     needs: [tests]
     runs-on: ubuntu-latest
     steps:
-      - run: 'echo tests completed'
+      - run: true

.github/workflows/node-tens.yml

@@ -15,4 +15,4 @@ jobs:
     needs: [tests]
     runs-on: ubuntu-latest
     steps:
-      - run: 'echo tests completed'
+      - run: true

index.d.ts

@@ -0,0 +1,3 @@
+declare function isArrayBuffer(value: unknown): value is ArrayBuffer;
+
+export = isArrayBuffer;

index.js

@@ -4,23 +4,27 @@ var callBind = require('call-bind');
 var callBound = require('call-bind/callBound');
 var GetIntrinsic = require('get-intrinsic');
 
-var $ArrayBuffer = GetIntrinsic('ArrayBuffer', true);
+var $ArrayBuffer = GetIntrinsic('%ArrayBuffer%', true);
+/** @type {undefined | ((receiver: ArrayBuffer) => number) | ((receiver: unknown) => never)} */
 var $byteLength = callBound('ArrayBuffer.prototype.byteLength', true);
 var $toString = callBound('Object.prototype.toString');
 
 // in node 0.10, ArrayBuffers have no prototype methods, but have an own slot-checking `slice` method
-var abSlice = $ArrayBuffer && !$byteLength && new $ArrayBuffer().slice;
-var $abSlice = abSlice && callBind(abSlice);
+var abSlice = !!$ArrayBuffer && !$byteLength && new $ArrayBuffer(0).slice;
+var $abSlice = !!abSlice && callBind(abSlice);
 
+/** @type {import('.')} */
 module.exports = $byteLength || $abSlice
 	? function isArrayBuffer(obj) {
 		if (!obj || typeof obj !== 'object') {
 			return false;
 		}
 		try {
 			if ($byteLength) {
+				// @ts-expect-error no idea why TS can't handle the overload
 				$byteLength(obj);
 			} else {
+				// @ts-expect-error TS chooses not to type-narrow inside a closure
 				$abSlice(obj, 0);
 			}
 			return true;
@@ -30,7 +34,7 @@ module.exports = $byteLength || $abSlice
 	}
 	: $ArrayBuffer
 		// in node 0.8, ArrayBuffers have no prototype or own methods, but also no Symbol.toStringTag
-		? function IsArrayBuffer(obj) {
+		? function isArrayBuffer(obj) {
 			return $toString(obj) === '[object ArrayBuffer]';
 		}
 		: function isArrayBuffer(obj) { // eslint-disable-line no-unused-vars

package.json

@@ -7,12 +7,14 @@
 		".": "./index.js",
 		"./package.json": "./package.json"
 	},
+	"types": "./index.d.ts",
 	"sideEffects": false,
 	"scripts": {
 		"prepack": "npmignore --auto --commentLines=autogenerated",
 		"prepublishOnly": "safe-publish-latest",
 		"prepublish": "not-in-publish || npm run prepublishOnly",
 		"lint": "eslint --ext=.js,.mjs .",
+		"postlint": "tsc -p .",
 		"pretest": "npm run lint",
 		"tests-only": "nyc tape 'test/**/*.js'",
 		"test": "npm run tests-only --",
@@ -43,6 +45,12 @@
 	"homepage": "https://github.com/inspect-js/is-array-buffer#readme",
 	"devDependencies": {
 		"@ljharb/eslint-config": "^21.1.0",
+		"@types/call-bind": "^1.0.5",
+		"@types/es-value-fixtures": "^1.4.4",
+		"@types/for-each": "^0.3.3",
+		"@types/get-intrinsic": "^1.2.2",
+		"@types/object-inspect": "^1.8.4",
+		"@types/tape": "^5.6.4",
 		"aud": "^2.0.4",
 		"auto-changelog": "^2.4.0",
 		"available-typed-arrays": "^1.0.6",
@@ -54,7 +62,8 @@
 		"nyc": "^10.3.2",
 		"object-inspect": "^1.13.1",
 		"safe-publish-latest": "^2.0.0",
-		"tape": "^5.7.4"
+		"tape": "^5.7.4",
+		"typescript": "next"
 	},
 	"auto-changelog": {
 		"output": "CHANGELOG.md",

test/index.js

@@ -11,15 +11,19 @@ var isArrayBuffer = require('..');
 test('isArrayBuffer', function (t) {
 	t.equal(typeof isArrayBuffer, 'function', 'is a function');
 
-	var nonABs = v.primitives.concat(
+	/** @type {unknown[]} */
+	var nonABs = [].concat(
+		// @ts-expect-error TS sucks with [].concat
+		v.primitives,
 		v.objects,
-		typeof SharedArrayBuffer === 'function' ? new SharedArrayBuffer() : []
+		typeof SharedArrayBuffer === 'function' ? new SharedArrayBuffer(0) : []
 	);
 	forEach(nonABs, function (nonAB) {
 		t.equal(isArrayBuffer(nonAB), false, inspect(nonAB) + ' is not an ArrayBuffer');
 	});
 
 	t.test('actual ArrayBuffer instances', { skip: typeof ArrayBuffer === 'undefined' }, function (st) {
+		// @ts-expect-error TS grumbles about 0 args
 		var ab = new ArrayBuffer();
 		st.equal(isArrayBuffer(ab), true, inspect(ab) + ' is an ArrayBuffer');
 

tsconfig.json

@@ -0,0 +1,49 @@
+{
+  "compilerOptions": {
+    /* Visit https://aka.ms/tsconfig to read more about this file */
+
+    /* Projects */
+
+    /* Language and Environment */
+    "target": "ESNext",                                  /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
+    // "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */
+    // "noLib": true,                                    /* Disable including any library files, including the default lib.d.ts. */
+    "useDefineForClassFields": true,                     /* Emit ECMAScript-standard-compliant class fields. */
+    // "moduleDetection": "auto",                        /* Control what method is used to detect module-format JS files. */
+
+    /* Modules */
+    "module": "commonjs",                                /* Specify what module code is generated. */
+    // "rootDir": "./",                                  /* Specify the root folder within your source files. */
+    // "moduleResolution": "node10",                     /* Specify how TypeScript looks up a file from a given module specifier. */
+    // "baseUrl": "./",                                  /* Specify the base directory to resolve non-relative module names. */
+    // "paths": {},                                      /* Specify a set of entries that re-map imports to additional lookup locations. */
+    // "rootDirs": [],                                   /* Allow multiple folders to be treated as one when resolving modules. */
+    "typeRoots": ["types"],                              /* Specify multiple folders that act like './node_modules/@types'. */
+    "resolveJsonModule": true,                           /* Enable importing .json files. */
+    // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
+
+    /* JavaScript Support */
+    "allowJs": true,                                     /* Allow JavaScript files to be a part of your program. Use the 'checkJS' option to get errors from these files. */
+    "checkJs": true,                                     /* Enable error reporting in type-checked JavaScript files. */
+    "maxNodeModuleJsDepth": 0,                           /* Specify the maximum folder depth used for checking JavaScript files from 'node_modules'. Only applicable with 'allowJs'. */
+
+    /* Emit */
+    "declaration": true,                                 /* Generate .d.ts files from TypeScript and JavaScript files in your project. */
+    "declarationMap": true,                              /* Create sourcemaps for d.ts files. */
+    "noEmit": true,                                      /* Disable emitting files from a compilation. */
+
+    /* Interop Constraints */
+    "allowSyntheticDefaultImports": true,                /* Allow 'import x from y' when a module doesn't have a default export. */
+    "esModuleInterop": true,                             /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables 'allowSyntheticDefaultImports' for type compatibility. */
+    "forceConsistentCasingInFileNames": true,            /* Ensure that casing is correct in imports. */
+
+    /* Type Checking */
+    "strict": true,                                      /* Enable all strict type-checking options. */
+
+    /* Completeness */
+    //"skipLibCheck": true                                 /* Skip type checking all .d.ts files. */
+  },
+  "exclude": [
+    "coverage"
+  ]
+}