WritableSignal<T>
WritableSignal<T> is an Angular signal whose stored value can be changed through writable operations.
Pro Angular 16
A writable signal is an Angular signal whose value can be changed directly through writable operations.
- How it is used
- Represents mutable application state and drives updates to related Angular template values.
- How deep it goes
- Explains creation, reading, set, update, mutate, and asReadonly, then stops short of broader signal internals.
- Examples
- Demonstrates a toggled index, product data repository, and shopping cart with incrementally modified selections.
- What you can do after
- Build mutable Angular state, update it with named writable methods, and expose controlled read-only views.
Modern Angular
A writable signal is an Angular signal whose stored value can be changed directly through its write operations.
- How it is used
- Uses WritableSignal<T> for directly controlled local or service state while reserving derived and observable-backed signals for read-only values.
- How deep it goes
- Explains typing, invocation, mutability boundaries, and readonly exposure, but does not detail every write operation's implementation.
- Examples
- Uses numeric and string-array signals, private service state, and a time-off request filter.
- What you can do after
- Evaluate and apply WritableSignal<T> by typing state, reading it through invocation, and controlling consumer access with asReadonly().
Related concepts
- signalproduced by · A signal is an observable value, event, or pattern that conveys information about a condition, state, or phenomenon.
- read-only signaluses · The asReadonly method creates a read-only view of a writable signal that exposes its current value without direct mutation operations.
- computed signalcontrasts with · A computed signal is a read-only reactive value derived from other signals and recalculated when its dependencies change.
- mutate methoduses · The mutate method changes a writable Angular signal based on its current value.
- assignmentcontrasts with · Assignment is a programming-language operation that binds or stores an evaluated value in a variable, property, or other assignable location.
- event bindingused by · Event binding is an association between an event and the expression or handler that responds when the event occurs.
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