array.prototype.copywithin

An ES2015 spec-compliant Array.prototype.copyWithin 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.copyWithin depends on a receiver (the “this” value), the main export takes the array to operate on as the first argument.

Example

var copyWithin = require('array.prototype.copywithin');
var assert = require('assert');

var arr = [1, 2, 3, 4, 5];
assert.deepEqual(copyWithin(arr, 0, 3), [4, 5, 3, 4, 5]);
assert.deepEqual(arr, [4, 5, 3, 4, 5]);

var copyWithin = require('array.prototype.copywithin');
var assert = require('assert');
/* when Array#copyWithin is not present */
delete Array.prototype.copyWithin;
var shimmedCopyWithin = copyWithin.shim();
assert.deepStrictEqual(shimmedCopyWithin, copyWithin.getPolyfill());

var arr = [1, 2, 3, 4, 5];
assert.deepEqual(copyWithin(arr, 0, 3), [4, 5, 3, 4, 5]);
assert.deepEqual(arr, [4, 5, 3, 4, 5]);

var copyWithin = require('array.prototype.copywithin');
var assert = require('assert');
/* when Array#copyWithin is present */
var shimmedCopyWithin = copyWithin.shim();
assert.equal(shimmedCopyWithin, Array.prototype.copyWithin);

var arr = [1, 2, 3, 4, 5];
assert.deepEqual(copyWithin(arr, 0, 3), [4, 5, 3, 4, 5]);
assert.deepEqual(arr, [4, 5, 3, 4, 5]);

Tests

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