@node-libraries/semaphore

Implement virtual semaphore for asynchronous processing

usage

1// Importing packages
2import { semaphore } from "@node-libraries/semaphore";
3// Instance Creation
4const s = semaphore();
5// Synchronization Lock
6await s.acquire();
7// Synchronization lock release
8s.release();
9// Wait until all locks are unlocked.
10await s.all();

1// Specify maximum number of parallels
2const s = semaphore(5);

example

1import { semaphore } from "@node-libraries/semaphore";
2
3const f = (value: string) =>
4  new Promise<void>((resolve) => {
5    console.timeLog("debug", value);
6    setTimeout(resolve, 1000);
7  });
8
9const main = async () => {
10  console.time("debug");
11  const s = semaphore();
12  ["A", "B", "C", "D", "E"].forEach(async (v) => {
13    await s.acquire();
14    await f(v);
15    s.release();
16  });
17  await s.all(); // Wait for everything to be finished.
18  console.timeLog("debug", "end");
19};
20main();
21
22/* Result
23debug: 0.197ms A
24debug: 1.014s B
25debug: 2.027s C
26debug: 3.039s D
27debug: 4.040s E
28debug: 5.050s end
29*/

1import { semaphore } from "@node-libraries/semaphore";
2
3const f = (value: string) =>
4  new Promise<void>((resolve) => {
5    console.timeLog("debug", value);
6    setTimeout(resolve, 1000);
7  });
8
9const main = async () => {
10  console.time("debug");
11  const s = semaphore(2);
12  ["A", "B", "C", "D", "E"].forEach(async (v) => {
13    await s.acquire();
14    await f(v);
15    s.release();
16  });
17  await s.all(); // Wait for everything to be finished.
18  console.timeLog("debug", "end");
19};
20main();
21
22/* Result
23debug: 0.19ms A
24debug: 1.826ms B
25debug: 1.005s C
26debug: 1.005s D
27debug: 2.012s E
28debug: 3.028s end
29*/