Rx.Observable.fromPromise(promise)

将一个兼容Promises/A+规范或 ES2015规范的 Promise 转化为 Obseervable

参数

1. promise (Promise): 兼容Promises/A+规范或 ES2015规范的 Promise

返回值

(Observable): 一个Observable，封装现有的Promises成功和失败接口。

例

Create a promise which resolves 42

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

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

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

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

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

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

// => Error: Error: reason