how to use the observable function from the rxjs library in javascript

npm install rxjs
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index.tsx
import { Observable } from 'rxjs';
import { map, filter, take } from 'rxjs/operators';
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index.tsx
const myObservable = new Observable(observer => {
  observer.next('Hello');
  observer.next('World');
  observer.complete();
});
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index.tsx
myObservable.subscribe({
  next: value => console.log(value),
  error: error => console.log(error),
  complete: () => console.log('Observation complete')
});
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index.tsx
myObservable.pipe(
  map(value => value.toUpperCase()),
  filter(value => value.startsWith('H')),
  take(1)
).subscribe(
  value => console.log(value)
);
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