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### `Rx.Observable.prototype.isEmpty()`
[Ⓢ](https://github.com/Reactive-Extensions/RxJS/blob/master/src/core/linq/observable/isempty.js "View in source")
Determines whether an observable sequence is empty.
#### Returns
*(`Observable`)*: An observable sequence containing a single element determining whether the source sequence is empty.
#### Example
```js
/* Not empty */
var source = Rx.Observable.range(0, 5)
.isEmpty()
var subscription = source.subscribe(
function (x) {
console.log('Next: ' + x);
},
function (err) {
console.log('Error: ' + err);
},
function () {
console.log('Completed');
});
// => Next: false
// => Completed
/* Empty */
var source = Rx.Observable.empty()
.isEmpty()
var subscription = source.subscribe(
function (x) {
console.log('Next: ' + x);
},
function (err) {
console.log('Error: ' + err);
},
function () {
console.log('Completed');
});
// => Next: true
// => Completed
```
### Location
File:
- [`/src/core/linq/observable/isempty.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/src/core/linq/observable/isempty.js)
Dist:
- [`rx.all.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/dist/rx.all.js)
- [`rx.all.compat.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/dist/rx.all.js)
- [`rx.aggregates.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/dist/rx.aggregates.js)
Prerequisites:
- [`rx.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/dist/rx.js) | [`rx.compat.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/dist/rx.compat.js) | [`rx.lite.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/dist/rx.lite.js) | [`rx.lite.compat.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/dist/rx.lite.compat.js)
NPM Packages:
- [`rx`](https://www.npmjs.org/package/rx)
NuGet Packages:
- [`RxJS-All`](http://www.nuget.org/packages/RxJS-All/)
- [`RxJS-Aggregates`](http://www.nuget.org/packages/RxJS-Aggregates/)
Unit Tests:
- [`/tests/observable/isempty.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/tests/observable/isempty.js)
|
