What is the difference between combineLatest and merge in RxJS?

What is the difference between combineLatest and merge in RxJS?

combineLatest and merge are both RxJS operators used to combine multiple observables, but they work differently. combineLatest emits the latest values from each observable whenever any of them emit, while merge emits values as they come in, regardless of the other observables.

Can you give me an example of how to use combineLatest?

Sure! Here's a simple example:

import { combineLatest, of } from 'rxjs';

const obs1 = of(1, 2, 3);
const obs2 = of('A', 'B', 'C');

combineLatest([obs1, obs2]).subscribe(([num, char]) => {
  console.log(`Number: ${num}, Character: ${char}`);
});

This will emit the latest values from both observables whenever either emits.

What about merge? Can you show me that too?

Absolutely! Here's how you can use merge:

import { merge, of } from 'rxjs';

const obs1 = of(1, 2, 3);
const obs2 = of('A', 'B', 'C');

merge(obs1, obs2).subscribe(value => {
  console.log(value);
});

This will emit values from both observables as they come in, in the order they are emitted.

When should I use combineLatest over merge?

Use combineLatest when you need the latest values from all observables at once, and use merge when you want to handle values as they arrive, without waiting for all observables to emit.