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surrealdb.js

mutex

The mutex decorator ensures that one or more class methods are executed asynchronously with a concurrency of 1.

Import

import { mutex } from "@tai-kun/surrealdb/utils";

Usage

function mutex(
  target: (...args: any) => PromiseLike<any>,
  context: ClassMethodDecoratorContext,
): (this: any, ...args: any) => Promise<any>;

Arguments

target

The class method.

context

The Stage 3 class method decorator context.

Return Value

An asynchronous function with concurrency limited to 1.

Example

The following example demonstrates the difference in execution timing of asynchronous operations with and without mutex:

import { mutex } from "@tai-kun/surrealdb/utils";


class Runner {
  async runWithoutMutex(ms: number, value: string) {
    await sleep(ms);
    console.log(value);
  }


  @mutex
  async runWithMutex(ms: number, value: string) {
    await sleep(ms);
    console.log(value);
  }
}


const runner = new Runner();
// without mutex
await Promise.all([
  runner.runWithoutMutex(1000, "A"),
  runner.runWithoutMutex(500, "B"),
  runner.runWithoutMutex(0, "C"),
]);
// with mutex
await Promise.all([
  runner.runWithMutex(1000, "A"),
  runner.runWithMutex(500, "B"),
  runner.runWithMutex(0, "C"),
]);

Output:

C
B
A
A
B
C