array.prototype.findlastindex Version Badge

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An ESnext spec-compliant Array.prototype.findLastIndex shim/polyfill/replacement that works as far down as ES3.

This package implements the es-shim API interface. It works in an ES3-supported environment and complies with the proposed spec.

Because Array.prototype.findLastIndex depends on a receiver (the this value), the main export takes the array to operate on as the first argument.

Getting started

sh npm install --save array.prototype.findlastindex

Usage/Examples

```js var findLastIndex = require('array.prototype.findlastindex'); var assert = require('assert');

var arr = [1, [2], [], 3, [[4]]]; var isNumber = function (x) { return typeof x === 'number' };

assert.deepEqual(findLastIndex(arr, isNumber), 3); ```

```js var findLastIndex = require('array.prototype.findlastindex'); var assert = require('assert'); / when Array#findLastIndex is not present / delete Array.prototype.findLastIndex; var shimmed = findLastIndex.shim();

assert.equal(shimmed, findLastIndex.getPolyfill()); assert.deepEqual(arr.findLastIndex(isNumber), findLastIndex(arr, isNumber)); ```

```js var findLastIndex = require('array.prototype.findlastindex'); var assert = require('assert'); / when Array#findLastIndex is present / var shimmed = findLastIndex.shim();

assert.equal(shimmed, Array.prototype.findLastIndex); assert.deepEqual(arr.findLastIndex(isNumber), findLastIndex(arr, isNumber)); ```

Tests

Simply clone the repo, npm install, and run npm test