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

The delay() function in RxJS library is used to delay the emission of values from an observable with a given duration. It is a transformation operator that returns an observable that emits the same values as the source observable, but delayed by a specified amount of time.

Here's an example of using the delay() function in JavaScript with observables:

index.tsx
import { of } from 'rxjs'; 
import { delay } from 'rxjs/operators'; 

// create an observable that emits values 1 to 5
const sourceObservable = of(1, 2, 3, 4, 5);

// delay each emission by 1 second
const delayedObservable = sourceObservable.pipe(delay(1000));

// subscribe to the delayed observable
delayedObservable.subscribe(value => console.log(value));
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In the above code, we imported of() from the RxJS library to create an observable that emits the values 1 to 5. We then used the delay() operator to delay the emission of each value by 1 second. Finally, we subscribed to the delayed observable and logged each emitted value to the console.

We can also use the delay() function with async/await syntax as shown below:

index.tsx
import { of } from 'rxjs'; 
import { delay } from 'rxjs/operators'; 

async function delayedValues() {
  // create an observable that emits values 1 to 5
  const sourceObservable = of(1, 2, 3, 4, 5);

  // delay each emission by 1 second
  const delayedObservable = sourceObservable.pipe(delay(1000)).toPromise();

  // wait for the delayed observable to complete
  const values = await delayedObservable;

  // log the emitted values
  console.log(values);
}

delayedValues();
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In this example, we created an async function called delayedValues() that uses the delay() operator to delay the emission of values by 1 second. We converted the observable to a promise object using the toPromise() function and then waited for the promise to resolve using the await keyword. Finally, we logged the emitted values to the console.