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November 4, 2025
Emran Hossain

Few frequently used operators and features in RxJS Observables and when to use them.

The RxJS operators you actually reach for with Observables: what each one does, when to use it, and short examples you can drop into real code.

RxJS logo with a data stream passing through a transform node, illustrating RxJS operators

There are several ways to deal with the asynchronous nature of our javaScript application. Earlier times, callback() was used heavily unless javaScript Promises and Observables were introduced.

The reason Observables are preferred over Promises is, it already contains the features of Promises plus it has much more other features to it.

Observables provides several operators which are very useful at times or absolutely necessary to know.

Here are some of these operators and what are the use cases where they can be used?

When it is enough for your asynchronous functionality to get only a single return event like a promise you can use

So,

To promise is

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