Creates an optimistic update function for a signal
optimistic
Functioncommon/interactive/optimistic
projects/common/interactive/optimistic/optimistic.ts
Description#
Creates an optimistic update function for a signal.
Sets the new value immediately (optimistic), then confirms via the async action. On success, applies the server-confirmed value. On failure, rolls back to the previous value.
This is a utility function, not a directive — it composes with any signal.
readonly name = signal('Alice');
readonly [updateName, nameState] = optimistic(
this.name,
(value) => this.http.put('/api/name', { name: value })
);
// In template:
<input [value]="name()" (change)="updateName($event.target.value)" />
<ng-container [cngxToastOn]="nameState.state" toastError="Update failed" />Signature#
optimistic(current: WritableSignal, action)Parameters#
- The writable signal to update optimistically.
@paramaction
- Async action that confirms the value. Should return the confirmed value.
Returns#
unknown Tuple of [applyFn, state].