asyncAdapter

Take functions with a callback pattern and use them with async/await!

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Installation

Using yarn:

yarn add async-adapter

Using npm:

npm i async-adapter

The package has CommonJS and ECMAScript Module builds; just import the package the way your bundler supports:

// ESM
import asyncAdapter from 'async-adapter';

// CommonJS
const asyncAdapter = require('async-adapter');

Usage

The first argument to the adapter is the original function name, and the rest of the arguments constitute any arguments you would pass to the original function, in the same order.

Note that you should not pass a function in the callback parameter's position into the asyncAdapter arguments, unless that function can return a value (e.g. not for an AJAX/Promise-based function).

Here is an example of an asynchronous function being used with asyncAdapter:

import asyncAdapter from 'async-adapter';

// Original funciton with callback
function httpGET(endpoint, callback) {
  var xhr = new XMLHttpRequest();
  xhr.addEventListener("readystatechange", function() {
    if (this.readyState == 4 && this.status == 200) {
      callback(JSON.parse(xhr.responseText));
    }
  });
  xhr.open("GET", endpoint);
  xhr.send();
}

const asyncHttpGET = asyncAdapter(httpGET, "https://example.com/api/data");

(async function someAsyncFunction() {
  const data = await asyncHttpGET;
  console.log(data); // -> { foo: 'bar' }
})();

Here is an example of a synchronous function being used with asyncAdapter:

import asyncAdapter from 'async-adapter';

// Original function
const add = (n1, n2, callback) => callback(n1 + n2);

// Add callback function to return value
const asyncSum20 = asyncAdapter(add, 10, 10, n => n);

// Add callback function to return value with side effects
const asyncSum50 = asyncAdapter(add, 10, 10, n => n + 30);

// Use inside function to create DRY async version of original function
const asyncSum = (n1, n2, n3) => asyncAdapter(add, n1, n2, n => n + n3);

(async function someAsyncFunction() {
  const sum20 = await asyncSum20;
  const sum50 = await asyncSum50;
  const sum100 = await asyncSum(5, 20, 75);

  console.log(sum20); // -> 20
  console.log(sum50); // -> 50
  console.log(sum100); // -> 100
});

License

MIT