source: imaps-frontend/node_modules/object.assign/README.md@ d565449

# object.assign <sup>[![Version Badge][npm-version-svg]][npm-url]</sup>

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

This package implements the [es-shim API](https://github.com/es-shims/api) interface. It works in an ES3-supported environment and complies with the [spec](http://www.ecma-international.org/ecma-262/6.0/#sec-object.assign). In an ES6 environment, it will also work properly with `Symbol`s.

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:
```js
var assign = require('object.assign').getPolyfill(); // returns native method if compliant
        /* or */
var assign = require('object.assign/polyfill')(); // returns native method if compliant
```

## Example

```js
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!
```

```js
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
});
```

```js
/* 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));
```

```js
/* 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`

[npm-url]: https://npmjs.org/package/object.assign
[npm-version-svg]: http://versionbadg.es/ljharb/object.assign.svg
[travis-svg]: https://travis-ci.org/ljharb/object.assign.svg
[travis-url]: https://travis-ci.org/ljharb/object.assign
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[deps-url]: https://david-dm.org/ljharb/object.assign
[dev-deps-svg]: https://david-dm.org/ljharb/object.assign/dev-status.svg?theme=shields.io
[dev-deps-url]: https://david-dm.org/ljharb/object.assign#info=devDependencies
[npm-badge-png]: https://nodei.co/npm/object.assign.png?downloads=true&stars=true
[license-image]: http://img.shields.io/npm/l/object.assign.svg
[license-url]: LICENSE
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