# mapTo

#### signature: `mapTo(value: any): Observable`

## Map emissions to constant value.

{% hint style="info" %}
New to transformation operators? Check out the article [Get started transforming streams with map, pluck, and mapTo](/learn-rxjs/concepts/get-started-transforming.md)!
{% endhint %}

### Examples

**Example 1: Map every emission to string**

( [StackBlitz](https://stackblitz.com/edit/typescript-fipd7a?file=index.ts\&devtoolsheight=100) | [jsBin](http://jsbin.com/qujolenili/1/edit?js,console) | [jsFiddle](https://jsfiddle.net/btroncone/4ojq56ng/) )

```js
// RxJS v6+
import { interval } from 'rxjs';
import { mapTo } from 'rxjs/operators';

//emit value every two seconds
const source = interval(2000);
//map all emissions to one value
const example = source.pipe(mapTo('HELLO WORLD!'));
//output: 'HELLO WORLD!'...'HELLO WORLD!'...'HELLO WORLD!'...
const subscribe = example.subscribe(val => console.log(val));
```

**Example 2: Mapping clicks to string**

( [StackBlitz](https://stackblitz.com/edit/typescript-btghci?file=index.ts\&devtoolsheight=100) | [jsBin](http://jsbin.com/xaheciwara/1/edit?js,console,output) | [jsFiddle](https://jsfiddle.net/btroncone/52fqL4nn/) )

```js
// RxJS v6+
import { fromEvent } from 'rxjs';
import { mapTo } from 'rxjs/operators';

//emit every click on document
const source = fromEvent(document, 'click');
//map all emissions to one value
const example = source.pipe(mapTo('GOODBYE WORLD!'));
//output: (click)'GOODBYE WORLD!'...
const subscribe = example.subscribe(val => console.log(val));
```

### Related Recipes

* [HTTP Polling](/learn-rxjs/recipes/http-polling.md)
* [Save Indicator](/learn-rxjs/recipes/save-indicator.md)
* [Smart Counter](/learn-rxjs/recipes/smartcounter.md)
* [Stop Watch](/learn-rxjs/recipes/stop-watch.md)

### Additional Resources

* [mapTo](https://rxjs.dev/api/operators/mapTo) 📰 - Official docs
* [Changing behavior with mapTo](https://egghead.io/lessons/rxjs-changing-behavior-with-mapto?course=step-by-step-async-javascript-with-rxjs) 🎥 💵 - John Linquist
* [Transformation operator: map and mapTo](https://egghead.io/lessons/rxjs-transformation-operator-map-and-mapto?course=rxjs-beyond-the-basics-operators-in-depth) 🎥 💵 - André Staltz

***

> 📁 Source Code: <https://github.com/ReactiveX/rxjs/blob/master/packages/rxjs/src/internal/operators/mapTo.ts>


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