What is WritableSignal?

AngularJunior~1 min read

WritableSignal is the type of a signal that can be changed. It allows not only reading the value but also changing it via set() and update().

To put it simply, for a junior:

signal() → creates a WritableSignal
such a signal can be read (counter())
and written (counter.set(...) or counter.update(...))

Example:

import { signal, WritableSignal } from '@angular/core';

const counter: WritableSignal<number> = signal(0);

counter();         // read
counter.set(10);   // set a new value
counter.update(v => v + 1); // change based on the old one

So WritableSignal is an ordinary signal that holds a value and allows it to be changed.

Short Answer

Interview ready

Premium

A concise answer to help you respond confidently on this topic during an interview.