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An ES2015 spec-compliant Array.prototype.keys 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 spec.

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

Example

``js
var keys = require('array.prototype.keys');
var assert = require('assert');
var iterate = require('iterate-iterator');

assert.deepEqual(iterate(keys([1, 2, 3])), [0, 1, 2]);
assert.deepEqual(iterate(keys([1, 0, 1])), [0, 1, 2]);
assert.deepEqual(iterate(keys([NaN])), [0]);
assert.deepEqual(iterate(keys([1,,3])), [0, 1, 2]);
`

`js
var keys = require('array.prototype.keys');
var assert = require('assert');
/ when Array#keys is not present /
delete Array.prototype.keys;
var shimmedMap = keys.shim();
assert.deepEqual(shimmedMap, keys.getPolyfill());
assert.deepEqual(iterate([1, 2, 3].keys()), [0, 1, 2]);
assert.deepEqual(iterate([1, 0, 1].keys()), [0, 1, 2]);
assert.deepEqual(iterate([NaN].keys()), [0]);
assert.deepEqual(iterate([1,,3].keys()), [0, 1, 2]);
`

`js
var keys = require('array.prototype.keys');
var assert = require('assert');
/ when Array#keys is present /
var shimmedMap = keys.shim();
assert.equal(shimmedMap, Array.prototype.keys);
assert.deepEqual(iterate([1, 2, 3].keys()), [0, 1, 2]);
`

Tests


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

[package-url]: https://npmjs.org/package/array.prototype.keys
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[dev-deps-url]: https://david-dm.org/es-shims/Array.prototype.keys#info=devDependencies
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[license-url]: LICENSE
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