Function signal

packages/core/src/render3/reactivity/signal.ts:72–89

(initialValue: T, options?: CreateSignalOptions<T>)

 * @see [Angular Signals](guide/signals)
 */
export function signal<T>(initialValue: T, options?: CreateSignalOptions<T>): WritableSignal<T> {
  const [get, set, update] = createSignal(initialValue, options?.equal);

  const signalFn = get as SignalGetter<T> & WritableSignal<T>;
  const node = signalFn[SIGNAL];

  signalFn.set = set;
  signalFn.update = update;
  signalFn.asReadonly = signalAsReadonlyFn.bind(signalFn as any) as () => Signal<T>;

  if (typeof ngDevMode !== 'undefined' && ngDevMode) {
    const debugName = options?.debugName;
    node.debugName = debugName;
    signalFn.toString = () => `[Signal${debugName ? ' (' + debugName + ')' : ''}: ${signalFn()}]`;
  }

  return signalFn as WritableSignal<T>;
}

export function signalAsReadonlyFn<T>(this: SignalGetter<T>): Signal<T> {
  const node = this[SIGNAL] as SignalNode<T> & {readonlyFn?: Signal<T>};