defer.md

Rx.Observable.defer(observableFactory)

Ⓢ

Returns an observable sequence that invokes the specified factory function whenever a new observer subscribes.

Arguments

1. observableFactory (Function): Observable factory function to invoke for each observer that subscribes to the resulting sequence.

Returns

(Observable): An observable sequence whose observers trigger an invocation of the given observable factory function.

Example

/* Using an observable sequence */
var source = Rx.Observable.defer(function () {
    return Rx.Observable.return(42);
});

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

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

/* Using a promise */
var source = Rx.Observable.defer(function () {
    return RSVP.Promise.resolve(42);
});

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

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

Location

File:

• /src/core/linq/observable/defer.js

Dist:

• rx.all.js
• rx.all.compat.js
• rx.js
• rx.compat.js
• rx.lite.js
• rx.lite.compat.js

Prerequisites:

• None

NPM Packages:

• rx

NuGet Packages:

• RxJS-Complete
• RxJS-Main
• RxJS-Lite

Unit Tests:

• /tests/observable/defer.js