doc/api/core/operators/interval.md
# This is RxJS v 4. [Find the latest version here](https://github.com/reactivex/rxjs)### `Rx.Observable.interval(period, [scheduler])`[Ⓢ](https://github.com/Reactive-Extensions/RxJS/blob/master/src/core/linq/observable/interval.js "View in source") Returns an observable sequence that produces a value after each period. #### Arguments1. `period` *(`Number`)*: Period for producing the values in the resulting sequence (specified as an integer denoting milliseconds).2. `[scheduler]` *(Scheduler=Rx.Scheduler.timeout)*: Scheduler to run the timer on. If not specified, Rx.Scheduler.timeout is used. #### Returns*(`Observable`)*: An observable sequence that produces a value after each period. Each value produced will default to a `Number` denoting its order in the timeline. (e.g. `0, 1, 2...`) #### Example```jsvar source = Rx.Observable .interval(500 /* ms */) .timeInterval() .take(3); var subscription = source.subscribe( function (x) { console.log('Next: ' + x); }, function (err) { console.log('Error: ' + err); }, function () { console.log('Completed'); }); // => Next: {value: 0, interval: 500}// => Next: {value: 1, interval: 500}// => Next: {value: 2, interval: 500}// => Completed``` ### Location File:- [/src/core/linq/observable/interval.js](https://github.com/Reactive-Extensions/RxJS/blob/master/src/core/linq/observable/interval.js) Dist:- [`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)- [`rx.time.js`](https://github.com/Reactive-Extensions/RxJS/blob/master/dist/rx.time.js) Prerequisites:- if `rx.time.js` - [`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`](https://www.npmjs.org/package/RxJS-Time)- [`RxJS-Time`](https://www.npmjs.org/package/RxJS-Time)- [`RxJS-Lite`](http://www.nuget.org/packages/RxJS-Lite/) Unit Tests:- [/tests/observable/interval.js](https://github.com/Reactive-Extensions/RxJS/blob/master/tests/observable/interval.js)