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Learn RxJS
mapTo
signature: mapTo(value: any): Observable
mapTo(value: any): ObservableMap emissions to constant value.
New to transformation operators? Check out the article Get started transforming streams with map, pluck, and mapTo!
Examples
Example 1: Map every emission to string
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// RxJS v6+
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import { interval } from 'rxjs';
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import { mapTo } from 'rxjs/operators';
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//emit value every two seconds
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const source = interval(2000);
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//map all emissions to one value
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const example = source.pipe(mapTo('HELLO WORLD!'));
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//output: 'HELLO WORLD!'...'HELLO WORLD!'...'HELLO WORLD!'...
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const subscribe = example.subscribe(val => console.log(val));
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Example 2: Mapping clicks to string
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// RxJS v6+
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import { fromEvent } from 'rxjs';
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import { mapTo } from 'rxjs/operators';
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//emit every click on document
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const source = fromEvent(document, 'click');
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//map all emissions to one value
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const example = source.pipe(mapTo('GOODBYE WORLD!'));
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//output: (click)'GOODBYE WORLD!'...
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const subscribe = example.subscribe(val => console.log(val));
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Related Recipes
Additional Resources
- 🎥 💵 - John Linquist
- 🎥 💵 - André Staltz
Last modified 2yr ago