object.assign

ES6 spec-compliant Object.assign shim. From https://github.com/es-shims/es6-shim

#object.assign

An Object.assign shim. Invoke its "shim" method to shim Object.assign if it is unavailable.

This package implements the es-shim API interface. It works in an ES3-supported environment and complies with the spec. In an ES6 environment, it will also work properly with Symbols.

Takes a minimum of 2 arguments: target and source. Takes a variable sized list of source arguments - at least 1, as many as you want. Throws a TypeError if the target argument is null or undefined.

Most common usage:

var assign = require('object.assign').getPolyfill(); // returns native method if compliant 
// Multiple sources! 
var target = { a: true };
var source1 = { b: true };
var source2 = { c: true };
var sourceN = { n: true };
 
var expected = {
    a: true,
    b: true,
    c: true,
    n: true
};
 
var assign = require('object.assign');
var assert = require('assert');
 
assign(target, source1, source2, sourceN);
assert.deepEqual(target, expected); // AWESOME! 
var assign = require('object.assign');
var assert = require('assert');
var target = {
    a: true,
    b: true,
    c: true
};
var source1 = {
    c: false,
    d: false
};
var sourceN = {
    e: false
};
 
var assigned = assign(target, source1, sourceN);
assert.equal(target, assigned); // returns the target object 
assert.deepEqual(assigned, {
    a: true,
    b: true,
    c: false,
    d: false,
    e: false
});
var assign = require('object.assign');
var assert = require('assert');
/* when Object.assign is not present */
delete Object.assign;
var shimmedAssign = assign.shim();
assert.equal(shimmedAssign, assign);
 
var target = {
    a: true,
    b: true,
    c: true
};
var source = {
    c: false,
    d: false,
    e: false
};
 
var assigned = assign(target, source);
assert.deepEqual(Object.assign(target, source), assign(target, source));
var assign = require('object.assign');
var assert = require('assert');
/* when Object.assign is present */
var shimmedAssign = assign.shim();
assert.equal(shimmedAssign, Object.assign);
 
var target = {
    a: true,
    b: true,
    c: true
};
var source = {
    c: false,
    d: false,
    e: false
};
 
assert.deepEqual(Object.assign(target, source), assign(target, source));

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