Rx.Observable.if(condition, thenSource, [elseSource])
Rx.Observable.ifThen(condition, thenSource, [elseSource])
DEPRECATED
Determines whether an observable collection contains values. There is an alias for this method called ifThen
for browsers <IE9
Arguments
condition
(Function
): The condition which determines if the thenSource or elseSource will be run.thenSource
(Observable
): thenSource The observable sequence that will be run if the condition function returns true.[elseSource]
(Observable|Scheduler): The observable sequence that will be run if the condition function returns false. If this is not provided, it defaults to Rx.Observabe.Empty with the specified scheduler.
Returns
(Observable
): The generated sequence.
Example
// This uses and only then source
var shouldRun = true;
var source = Rx.Observable.if(
function () { return shouldRun; },
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
// The next example uses an elseSource
var shouldRun = false;
var source = Rx.Observable.if(
function () { return shouldRun; },
Rx.Observable.return(42),
Rx.Observable.return(56)
);
var subscription = source.subscribe(
function (x) {
console.log('Next: ' + x);
},
function (err) {
console.log('Error: ' + err);
},
function () {
console.log('Completed');
});
// => Next: 56
// => Completed
Location
File:
Dist:
Prerequisites:
- If using
rx.experimental.js
-rx.js
|rx.compat.js
|rx.lite.js
|rx.lite.compat.js
NPM Packages:
NuGet Packages:
Unit Tests: