async-compat

async-compat

Convert synchronous, callback, and promise-returning functions to a callback interface.

Install

npm install async-compat

Usage

asyncFunction(fn, hasCallback, ...args, callback) invokes fn and calls the final callback with (err, result). Set hasCallback to true when fn expects a callback.

var compat = require('async-compat');

function syncFn(value) {
  return value * 2;
}

compat.asyncFunction(syncFn, false, 2, function (err, result) {
  if (err) throw err;
  console.log(result); // 4
});

function callbackFn(value, callback) {
  callback(null, value * 2);
}

compat.asyncFunction(callbackFn, true, 2, function (err, result) {
  if (err) throw err;
  console.log(result); // 4
});

function promiseFn(value) {
  return Promise.resolve(value * 2);
}

compat.asyncFunction(promiseFn, false, 2, function (err, result) {
  if (err) throw err;
  console.log(result); // 4
});

API

• asyncFunction(fn, hasCallback, ...args, callback) normalizes a synchronous, callback-based, or promise-returning function. Returned Error values and rejected promises reach the callback as err.
• asyncValue(value, callback) sends an Error, resolved promise value, or ordinary value to the callback.
• defaultValue(result, value) returns value only when result is undefined; otherwise it returns result.