simple-deferred2

A lightweight Deferred implementation for browser and Node.js, written in TypeScript.

Install

npm install simple-deferred2

Usage

import Deferred from 'simple-deferred2';

function fetchData() {
  const deferred = new Deferred<{ id: number }>();

  setTimeout(() => {
    deferred.resolve({ id: 1 });
  }, 1000);

  return deferred.promise;
}

fetchData().then((data) => {
  console.log(data); // { id: 1 }
});

With async/await

const deferred = new Deferred<string>();

socket.on('message', (msg) => {
  deferred.resolve(msg);
});

const message = await deferred.promise;
console.log(message);

Reject

const deferred = new Deferred<void>();

setTimeout(() => {
  deferred.reject(new Error('timeout'));
}, 5000);

try {
  await deferred.promise;
} catch (err) {
  console.error(err); // Error: timeout
}

API

new Deferred<T>()

Creates a new Deferred instance.

Properties:

| Property | Type | Description | | --- | --- | --- | | promise | Promise<T> | The inner Promise | | resolve | (value: T \| PromiseLike<T>) => void | Resolves the promise | | reject | (reason?: any) => void | Rejects the promise |

The instance is frozen after construction (Object.freeze).

License

MIT