PromiseDefer.js
PromiseDefer.js is a small Promise.defer
"polyfill" to create
a Deferred
object you can later resolve or reject and get
a Promise
out of. It used to exist in browsers and JavaScript engines as
Promise.defer
, but was later deprecated. It's still useful in some cases.
PromiseDefer.js uses the native ES6 Promise
by default, but you can pass
it another Promises/A+ compatible constructor function.
Installing
npm install promise-defer
PromiseDefer.js follows semantic versioning, so feel
free to depend on its major version with something like >= 1.0.0 < 2
(a.k.a ^1.0.0
).
Using
var defer = var deferred = deferreddeferredpromise // Will eventually be resolved with 42. var rejection = rejectionrejectionpromise // Will eventually be rejected with the error.
PromiseDefer.js will use the global ES6 Promise
constructor by default that's
starting to become available in browsers and JavaScript runtimes (e.g. the V8 in
Node.js v0.11). It doesn't therefore have any outside dependencies.
Using another Promise implementation
If you'd like to use another promise implementation or are running in an
environment that doesn't have the native Promise
, pass
a Promises/A+ compatible constructor as the first argument:
var Bluebird = var defer = promise // => An instance of Bluebird.
Deferred class
If you need to programmatically differentiate beteween regular objects and
Deferred
instances, use the instanceof
operator:
var Deferred = instanceof Deferred // => true
License
PromiseDefer.js is released under a Lesser GNU Affero General Public License, which in summary means:
- You can use this program for no cost.
- You can use this program for both personal and commercial reasons.
- You do not have to share your own program's code which uses this program.
- You have to share modifications (e.g. bug-fixes) you've made to this program.
For more convoluted language, see the LICENSE
file.
About
Andri Möll typed this and the code.
Monday Calendar supported the engineering work.
If you find PromiseDefer.js needs improving, please don't hesitate to type to me now at andri@dot.ee or create an issue online.