frompromise.md

Rx.Observable.fromPromise(promise)

Ⓢ

Converts a Promises/A+ spec compliant Promise and/or ES6 compliant Promise to an Observable sequence.

Arguments

1. promise (Promise): Promises/A+ spec compliant Promise to an Observable sequence.

Returns

(Observable): An Observable sequence which wraps the existing promise success and failure.

Example

// Create a promise which resolves 42
var promise1 = new RSVP.Promise(function (resolve, reject) {
    resolve(42);
});

var source1 = Rx.Observable.fromPromise(promise1);

var subscription1 = source1.subscribe(
    function (x) {
        console.log('Next: ' + x);
    },
    function (err) {
        console.log('Error: ' + err);
    },
    function () {
        console.log('Completed');
    });

// => Next: 42
// => Completed

// Create a promise which rejects with an error
var promise2 = new RSVP.Promise(function (resolve, reject) {
    reject(new Error('reason'));
});

var source2 = Rx.Observable.fromPromise(promise2);

var subscription2 = source2.subscribe(
    function (x) {
        console.log('Next: ' + x);
    },
    function (err) {
        console.log('Error: ' + err);
    },
    function () {
        console.log('Completed');
    });

// => Error: Error: reject

Location

File:

• /src/core/linq/observable/frompromise.js

Dist:

• rx.async.js
• rx.async.compat.js
• rx.lite.js
• rx.lite.compat.js

Prerequisites:

• If using rx.async.js | rx.async.compat.js
  • rx.js | rx.compat.js
  • rx.binding.js
• rx.lite.js | rx.lite.compat.js

NPM Packages:

• rx

NuGet Packages:

• RxJS-Async
• RxJS-Lite

Unit Tests:

• /tests/observable/fromnodecallback.js