Signal

Defined in: packages/async/src/synchro/signal.ts:56

A signal primitive for signaling between async tasks.

When the signal is in the signaled state, calls to wait will resolve immediately. When the signal is in the non-signaled state, calls to wait will block until the signal is signaled. Waiters are released in FIFO order.

The signal can be configured to auto-reset or manual-reset.

If autoReset is true, the signal will automatically reset to the non-signaled state after a single waiter is released, acting like a binary semaphore. If autoReset is false, the signal will remain in the signaled state until it is manually reset.

Examples

const signal = new Signal(true); // autoReset = true

  // Task 1
  async function task1() {
    console.log("Waiting for signal...");
    await signal.wait();
    console.log("Signal received!");
  }

  // Task 2
  async function task2() {
    console.log("Signaling...");
    signal.signal();
  }

  task1();
  task2();

const signal = new Signal(false); // autoReset = false

  // Task 1
  async function task1() {
    console.log("Waiting for signal...");
    await signal.wait();
    console.log("Signal received!");
  }

  // Task 2
  async function task2() {
    console.log("Signaling...");
    signal.signal();
  }

  task1();
  task2();
  task1(); // This will also proceed immediately since autoReset is false

Constructors

Constructor

new Signal(autoReset, initialState?): Signal

Defined in: packages/async/src/synchro/signal.ts:69

Creates a new Signal instance.

Parameters

autoReset

boolean

If true, the signal will automatically reset after releasing a waiter. If false, the signal will remain signaled until manually reset.

initialState?

boolean = false

The initial state of the signal. Default is false (non-signaled).

Returns

Signal

Accessors

signaled

Get Signature

get signaled(): boolean

Defined in: packages/async/src/synchro/signal.ts:77

Indicates whether the signal is in the signaled state.

Returns

boolean

Methods

reset()

reset(): void

Defined in: packages/async/src/synchro/signal.ts:97

Reset the signal to non-signaled state

Returns

void

---

signal()

signal(): void

Defined in: packages/async/src/synchro/signal.ts:90

Set the signal to signaled state

Notifies waiting listeners. If autoReset is true, only one listener will be notified and the signal will reset to non-signaled state. If autoReset is false, all listeners will be notified.

Listeners are notified asynchronously.

Returns

void

---

wait()

wait(signal?): Promise<void>

Defined in: packages/async/src/synchro/signal.ts:116

Wait for the signal to be signaled.

If the signal is already signaled, the listener is called immediately. If autoReset is true, the signal is reset to non-signaled state after notifying a listener.

Note: If multiple listeners are waiting and the signal is signaled, only one listener will be notified if autoReset is true. If autoReset is false, all listeners will be notified.

Parameters

signal?

AbortSignal | null

An AbortSignal that can be used to cancel the wait operation.

Returns

Promise<void>

A promise that resolves when the signal is signaled, or rejects when aborted.