Add support for TypedArray

index.js

@@ -1,14 +1,20 @@
 /* eslint-disable no-undefined */
 
+import { loose as isTypedArray } from 'is-typedarray';
+
 /**
- * @param  {string|Array} item
- * @param  {number} _index
+ * @param {string|Array} item
+ * @param {number} _index
  *
  * @returns {*}
  * @throws {TypeError}
  */
 export default function ponyfill(item, _index) {
-	if (typeof item !== 'string' && !Array.isArray(item)) {
+	if (
+		typeof item !== 'string' &&
+		!Array.isArray(item) &&
+		!isTypedArray(item)
+	) {
 		throw new TypeError('Expected a string or array-like item.');
 	}
 
@@ -26,7 +32,8 @@ export const preferNative = (item, index) => {
 	if (
 		(typeof item === 'string' &&
 			typeof String.prototype.at !== 'undefined') ||
-		(Array.isArray(item) && Array.prototype.at !== 'undefined')
+		(Array.isArray(item) && Array.prototype.at !== 'undefined') ||
+		(isTypedArray(item) && item.at !== 'undefined')
 	) {
 		return item.at(index);
 	}

package.json

@@ -36,6 +36,9 @@
     "test:automated:watch": "npm run test:automated -- --auto-watch --no-single-run",
     "version": "if [ $(git rev-parse --abbrev-ref HEAD) == 'master' ]; then version-changelog CHANGELOG.md && changelog-verify CHANGELOG.md && git add CHANGELOG.md; else echo; fi"
   },
+  "dependencies": {
+    "is-typedarray": "^1.0.0"
+  },
   "devDependencies": {
     "@babel/cli": "^7.2.3",
     "@babel/core": "^7.2.2",

rollup.config.js

@@ -3,6 +3,8 @@
 const path = require('path');
 const { promises: fs } = require('fs');
 const { default: babel } = require('@rollup/plugin-babel');
+const { default: resolve } = require('@rollup/plugin-node-resolve');
+const commonjs = require('@rollup/plugin-commonjs');
 
 module.exports = {
 	input: 'index.js',
@@ -49,6 +51,8 @@ module.exports = {
 		babel({
 			babelHelpers: 'bundled',
 			exclude: 'node_modules/**'
-		})
+		}),
+		resolve(),
+		commonjs()
 	]
 };

test/index.js

@@ -65,6 +65,28 @@ it('works for sparse arrays', function () {
 	assert.deepEqual(at(array, -1), [1]);
 });
 
+it('works for typed arrays', function () {
+	const array = new Int8Array([1, [2], [3, 4]]);
+
+	assert.equal(at(array, 0), array[0]);
+	assert.equal(at(array, -3), array[0]);
+
+	assert.deepEqual(at(array, 1), array[1]);
+	assert.deepEqual(at(array, -2), array[1]);
+
+	assert.deepEqual(at(array, 2), array[2]);
+	assert.deepEqual(at(array, -1), array[2]);
+
+	assert.equal(at(array, 3), undefined);
+	assert.equal(at(array, -4), undefined);
+
+	assert.equal(at([], 0), undefined);
+	assert.equal(at([], -1), undefined);
+
+	assert.equal(at([], Infinity), undefined);
+	assert.equal(at([], Infinity), undefined);
+});
+
 it('uses native implementation if it’s available', function () {
 	assert.equal(preferNative('abc', -1), 'c');
 });