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An implementation of the ES6 method
Array.prototype.findIndex as a standalone module and a
Finds an item in an array matching a predicate function, and returns its index.
Fast both when
thisArg is used and also when it isn't.
npm install find-index
var findIndex = require('find-index/findIndex') var findIndex = require('find-index/ponyfill') // will use native Array#findIndex if available. var findLastIndex = require('find-index/findLastIndex') // search backwards from end
findIndex(array, callback[, thisArg]) findLastIndex(array, callback[, thisArg]) Parameters: array The array to operate on. callback Function to execute on each value in the array, taking three arguments: element The current element being processed in the array. index The index of the current element being processed in the array. array The array findIndex was called upon. thisArg Object to use as this when executing callback.
Based on array-findindex
$ iojs --harmony_arrays perf/benchmark.js native Array.prototype.findIndex: 6347ms findIndex: 1633ms findIndex ponyfill: 6384ms findLastIndex: 1508ms npm lodash.findindex: 2900ms npm array-findindex: 3512ms