# promise.prototype.finally <sup>[![Version Badge][npm-version-svg]][package-url]</sup>

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ES Proposal spec-compliant shim for Promise.prototype.finally. Invoke its "shim" method to shim `Promise.prototype.finally` if it is unavailable or noncompliant. **Note**: a global `Promise` must already exist: the [es6-shim](https://github.com/es-shims/es6-shim) is recommended.

This package implements the [es-shim API](https://github.com/es-shims/api) interface. It works in an ES3-supported environment that has `Promise` available globally, and complies with the [proposed spec](https://github.com/tc39/proposal-promise-finally).

Most common usage:
```js
var assert = require('assert');
var promiseFinally = require('promise.prototype.finally');

var resolved = Promise.resolve(42);
var rejected = Promise.reject(-1);

promiseFinally(resolved, function () {
	assert.equal(arguments.length, 0);

	return Promise.resolve(true);
}).then(function (x) {
	assert.equal(x, 42);
});

promiseFinally(rejected, function () {
	assert.equal(arguments.length, 0);
}).catch(function (e) {
	assert.equal(e, -1);
});

promiseFinally(rejected, function () {
	assert.equal(arguments.length, 0);

	throw false;
}).catch(function (e) {
	assert.equal(e, false);
});

promiseFinally.shim(); // will be a no-op if not needed

resolved.finally(function () {
	assert.equal(arguments.length, 0);

	return Promise.resolve(true);
}).then(function (x) {
	assert.equal(x, 42);
});

rejected.finally(function () {
	assert.equal(arguments.length, 0);
}).catch(function (e) {
	assert.equal(e, -1);
});

rejected.finally(function () {
	assert.equal(arguments.length, 0);

	throw false;
}).catch(function (e) {
	assert.equal(e, false);
});
```

## Tests
Simply clone the repo, `npm install`, and run `npm test`

## Thanks
Huge thanks go out to [@matthew-andrews](https://github.com/matthew-andrews), who provided the npm package name for v2 of this module. v1 is both in [the original repo][v1-repo-url] and preserved in [a branch][v1-branch-url]

[package-url]: https://npmjs.com/package/promise.prototype.finally
[npm-version-svg]: http://versionbadg.es/es-shims/Promise.prototype.finally.svg
[travis-svg]: https://travis-ci.org/es-shims/Promise.prototype.finally.svg
[travis-url]: https://travis-ci.org/es-shims/Promise.prototype.finally
[deps-svg]: https://david-dm.org/es-shims/Promise.prototype.finally.svg
[deps-url]: https://david-dm.org/es-shims/Promise.prototype.finally
[dev-deps-svg]: https://david-dm.org/es-shims/Promise.prototype.finally/dev-status.svg
[dev-deps-url]: https://david-dm.org/es-shims/Promise.prototype.finally#info=devDependencies
[testling-svg]: https://ci.testling.com/es-shims/Promise.prototype.finally.png
[testling-url]: https://ci.testling.com/es-shims/Promise.prototype.finally
[npm-badge-png]: https://nodei.co/npm/promise.prototype.finally.png?downloads=true&stars=true
[license-image]: http://img.shields.io/npm/l/promise.prototype.finally.svg
[license-url]: LICENSE
[downloads-image]: http://img.shields.io/npm/dm/promise.prototype.finally.svg
[downloads-url]: http://npm-stat.com/charts.html?package=promise.prototype.finally
[v1-repo-url]: https://github.com/matthew-andrews/Promise.prototype.finally
[v1-branch-url]: https://github.com/es-shims/Promise.prototype.finally/tree/v1