https://github.com/vovkabelov/array.findindex

Lightweight Array.prototype.findIndex Polyfill. ES5. IE9+
https://github.com/vovkabelov/array.findindex

array es5 findindex ie9 javascript polyfill

Last synced: 12 months ago
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Lightweight Array.prototype.findIndex Polyfill. ES5. IE9+

• Host: GitHub
• URL: https://github.com/vovkabelov/array.findindex
• Owner: vovkabelov
• License: mit
• Created: 2017-11-14T19:34:30.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2017-11-24T20:00:21.000Z (over 8 years ago)
• Last Synced: 2025-07-13T07:51:57.191Z (about 1 year ago)
• Topics: array, es5, findindex, ie9, javascript, polyfill
• Language: JavaScript
• Homepage: https://vovkabelov.github.io/array.findIndex
• Size: 26.4 KB
• Stars: 2
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# Lightweight Array.prototype.findIndex polyfill

[![Build Status](https://travis-ci.org/vovkabelov/array.findIndex.svg?branch=master)](https://travis-ci.org/vovkabelov/array.findIndex)

[![Coverage Status](https://coveralls.io/repos/github/vovkabelov/array.findIndex/badge.svg?branch=master&service=Github)](https://coveralls.io/github/vovkabelov/array.findIndex?branch=master&service=Github)

[![Maintainability](https://api.codeclimate.com/v1/badges/5850f186343160e5f42c/maintainability)](https://codeclimate.com/github/vovkabelov/array.findIndex/maintainability)

[![Size](https://badges.herokuapp.com/size/github/vovkabelov/array.findIndex/master/src/array-find-index-polyfill.js?gzip=true)](https://raw.githubusercontent.com/vovkabelov/array.findIndex/master/dist/array-find-index-polyfill.min.js)

[![npm version](https://badge.fury.io/js/array.findindex.svg)](https://badge.fury.io/js/array.findindex)

The findIndex() method returns the index of the first element in the array 

that satisfies the provided testing function. Otherwise -1 is returned.

## How It Works

**1.** Download [Latest version](https://github.com/vovkabelov/array.findIndex/archive/master.zip) or install with bower 

`bower install array.findindex`  

**2.** Include polyfill on your web-page 

```html

```

**3.** Use as native method

```javascript

["apple", "banana", "peach"].findIndex(function(item) {

    return item === "banana";

});

// 1

```

## Performance

Testing in Chrome 61.0.3163 / Mac OS X 10.13.0  

**Native** 431,077 Ops/sec   

**Polyfill** 2,289,661 Ops/sec  

See [https://jsperf.com/array-prototype-find-index-polyfill](https://jsperf.com/array-prototype-find-index-polyfill)

## Links

[Specification](http://www.ecma-international.org/ecma-262/6.0/#sec-array.prototype.findindex) on "Ecma International"  

[MDN examples](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findIndex)

## Copyright and license

Code and documentation copyright 2017 Vladimir Belov. Code released under the [MIT license](https://github.com/vovkabelov/array.find/blob/master/LICENSE).