Typescript CriticalSection

criticalSection.ts

interface Pending {
  resolve: (value: any) => void;
  reject: (error: any) => void;
  criticalSection: () => Promise<unknown>;
}

export function criticalSection(): <T>(
  criticalSection: () => Promise<T>
) => Promise<T> {
  const pending: Pending[] = [];
  let running = false;

  return <T>(criticalSection: () => Promise<T>) => {
    return new Promise<T>((resolve, reject) => {
      (async () => {
        pending.push({ criticalSection, reject, resolve });

        if (!running) {
          running = true;

          while (pending.length) {
            const { criticalSection, reject, resolve } = pending.shift()!;
            try {
              resolve(await criticalSection());
            } catch (err) {
              reject(err);
            }
          }
          running = false;
        }
      })();
    });
  };
}

test.ts

import { criticalSection } from "./criticalSection.ts";

function waitFor(ms: number) {
  return new Promise<void>((resolve) => {
    setTimeout(() => resolve(), ms);
  });
}

const cs = criticalSection();

(async () => {
  await Promise.all([
    (async () => {
      await waitFor(1000);
      console.log("1000");
      await cs(async () => {
        console.log("1000");
        await waitFor(1000);
      });
      console.log("2000");
    })(),
    (async () => {
      await waitFor(1001);
      console.log("1001");
      await cs(async () => {
        console.log("2000");
        await waitFor(1000);
      });
      console.log("3000");
    })(),
  ]);

  function makeTestCriticalSection(name: string, ms: number) {
    return async () => {
      console.log(`${name} start`);
      await waitFor(ms);
      console.log(`${name} end`);
    };
  }

  setTimeout(() => cs(makeTestCriticalSection("first", 500)), 500);
  setTimeout(() => cs(makeTestCriticalSection("second", 500)), 501);
})();

/*

result:

1000
1000
1001
2000
2000
3000
first start
first end
second start
second end

*/

• [****](`

### url

`)

Yte3588

#jiiibejwjskakakka

• @mjy9088