Asyncctx NPM | npm.io

node-async-context (asyncctx)

This module allows you to create an asynchronous execution context for JavaScript or TypeScript

NOTE: This module is based on async_hooks an experimental built-in node.js module introduced in v8.0.0

Deprecation

NOTE: This module is now deprecated in favour of AsyncLocalStorage which is available for nodejs >= 12

quick start using AsyncLocalStorage

class ContinuationLocalStorage<T> extends AsyncLocalStorage<T> {
  public getContext(): T | undefined {
    return this.getStore();
  }
  public setContext(value: T): T {
    this.enterWith(value);
    return value;
  }
}

Introduction

To give you an idea of how asyncctx is supposed to be used:

import { ContinuationLocalStorage } from 'asyncctx';

class MyLocalStorage {
  value: number;
}

let cls = new ContinuationLocalStorage<MyLocalStorage>();
cls.setRootContext({ value: 1 });

process.nextTick(() => {
  let curr1 = cls.getContext(); // value is 1
  cls.setContext({ value: 2 }); // value should be 2 in the current execution context and below
  process.nextTick(() => {
    let curr2 = cls.getContext(); // value is 2
    cls.setContext({ value: 3 }); // value should be 3 in the current execution context and below
    process.nextTick(() => {
      let curr3 = cls.getContext(); // value is 3
    });
  });
  process.nextTick(() => {
    let curr4 = cls.getContext(); // value is 2
  });
});