# array-find-index [](https://travis-ci.org/sindresorhus/array-find-index) > ES2015 [`Array#findIndex()`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/findIndex) [ponyfill](https://ponyfill.com) ## Install ``` $ npm install --save array-find-index ``` ## Usage ```js const arrayFindIndex = require('array-find-index'); arrayFindIndex(['rainbow', 'unicorn', 'pony'], x => x === 'unicorn'); //=> 1 ``` ## API Same as `Array#findIndex()`, but with the input array as the first argument. ## License MIT © [Sindre Sorhus](https://sindresorhus.com)