ljharbobject.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
/* or */
var assign = require('object.assign/polyfill')(); // returns native method if compliantExample
var assert = require('assert');
// 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
};
assign(target, source1, source2, sourceN);
assert.deepEqual(target, expected); // AWESOME!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
});/* when Object.assign is not present */
delete Object.assign;
var shimmedAssign = require('object.assign').shim();
/* or */
var shimmedAssign = require('object.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));/* when Object.assign is present */
var shimmedAssign = require('object.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));Tests
Simply clone the repo, npm install, and run npm test