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 operators in RxJS used for combining multiple observables, but they work differently. combineLatest emits the latest values from each observable whenever any of them emits, while merge emits values from all observables as they come in.

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

Sure! Here's a simple example:

import { combineLatest, of } from 'rxjs';

const observable1 = of('Hello');
const observable2 = of('World');

combineLatest([observable1, observable2]).subscribe(([val1, val2]) => {
  console.log(`${val1} ${val2}`); // Outputs: Hello World
});

What about merge? How does that work?

With merge, you can combine multiple observables and get their emitted values as they come in. Here's an example:

import { merge, of } from 'rxjs';

const observable1 = of('Hello');
const observable2 = of('World');

merge(observable1, observable2).subscribe(value => {
  console.log(value); // Outputs: Hello then World
});

When should I use combineLatest instead of merge?

Use combineLatest when you need the latest values from all observables at once, and merge when you want to handle values as they arrive individually.