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Interface CountdownSignal

Queues callers until the counter reaches 0.

example
export function downloadAll(files = []) {
  const signal = signals.countdown(files.length);
  files.forEach(file =>
    download(file).finally(() =>
      signal.decrement()));
  return signal.ready();
}
example
import { registry } from '../some/component/registry';

const signal = signals.countdown();

export function loadComponent(component) {
  if (component in registry) {
    signal.increment();
    const script = document.createElement('script');
    script.async = true;
    script.type = 'text/javascript';
    script.src = registry[component];
    script.onload = () => signal.decrement(); // countdown
    document.body.appendChild(script);
  }
  return signal.ready();
}

Hierarchy

Index

Methods

Methods

decrement

  • decrement(count?: number): void

  • Subtracts the specified amount from the counter. When the counter reaches 0 it will be placed into an unblocked state, enabling any queued callers to proceed.

    example
    const signal = signals.countdown(3);

    async function doTask1() {
      // do stuff
      signal.decrement();
    }

    async function doTask2() {
      // do stuff
      signal.decrement();
    }

    async function doTask3() {
      // do stuff
      signal.decrement();
    }

    doTask1();
    doTask2();
    doTask3();

    export function ready() {
      return signal.ready();
    }

    Parameters

    • Optional count: number

      The number to subtract from the internal counter. Must be a positive integer.

    Returns void

increment

  • increment(count?: number): void

  • Places the signal into a blocked state. The signal will need to be decremented by a corresponding amount in order to unblock it.

    example
    const signal = signals.countdown();

    export function appendFilesToDownload(files = []) {
      signal.increment(files.length);
      files.forEach(file =>
        download(file).finally(() =>
          signal.decrement()));
      return signal.ready();
    }

    Parameters

    • Optional count: number

      The number to add to the internal counter. Must be a positive integer.

    Returns void

ready

  • ready(): Promise<void>

  • Queues the caller until the counter reaches 0. Once the counter reaches 0, all callers will be invoked in the order they were queued.

    example
    export function downloadAll(files = []) {
      const signal = signals.countdown(files.length);
      files.forEach(file =>
        download(file).finally(() =>
          signal.decrement()));
      return signal.ready();
    }

    Returns Promise<void>

    A Promise that will be resolved when the counter reaches 0.