array.prototype.concat 
An ES spec-compliant Array.prototype.concat 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.concat depends on a receiver (the “this” value), the main export takes the array to operate on as the first argument.
Engines where this is needed
Note: this list is not exhaustive.
- Safari 10 - 13
- Chrome 48+ (v8 bug)
- node 6+
Example
var concat = require('array.prototype.concat');
var assert = require('assert');
var a = [1, 1, 1];
assert.deepEqual(concat(a, 1, 2), [1, 1, 1, 1, 2]);
assert.deepEqual(a, [1, 1, 1]);var concat = require('array.prototype.concat');
var assert = require('assert');
/* when Array#concat is not present */
delete Array.prototype.concat;
var shimmed = concat.shim();
assert.equal(shimmed, concat.getPolyfill());
assert.equal(shimmed, Array.prototype.concat);
assert.deepEqual([1, 2, 3].concat(1, 2, 3), concat([1, 2, 3], 1, 2, 3));var concat = require('array.prototype.concat');
var assert = require('assert');
/* when Array#concat is present */
var shimmed = concat.shim();
assert.equal(shimmed, Array.prototype.concat);
assert.deepEqual([1, 2, 3].concat(1, 2, 3), concat([1, 2, 3], 1, 2, 3));Tests
Simply clone the repo, npm install, and run npm test
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