await-to-js

Async await wrapper for easy error handling

Pre-requisites

You need to use Node 7.6 (or later) or an ES7 transpiler in order to use async/await functionality. You can use babel or typescript for that.

Install

npm i await-to-js --save

Usage

import to from 'await-to-js';
// If you use CommonJS (i.e NodeJS environment), it should be:
// const to = require('await-to-js').default;

// This is new functionality
// --------
function someFuncWithError (someArg) {
  if (Math.random() > .5) {
    throw new Error("Error")
  } else {
    return 1
  }
}

function someFunc () {
  const [err, result] = to(() => someFuncWithError(1))
}
// --------

async function asyncTaskWithCb(cb) {
     let err, user, savedTask, notification;

     [ err, user ] = await to(UserModel.findById(1));
     if(!user) return cb('No user found');

     [ err, savedTask ] = await to(TaskModel({userId: user.id, name: 'Demo Task'}));
     if(err) return cb('Error occurred while saving task');

    if(user.notificationsEnabled) {
       [ err ] = await to(NotificationService.sendNotification(user.id, 'Task Created'));
       if(err) return cb('Error while sending notification');
    }

    if(savedTask.assignedUser.id !== user.id) {
       [ err, notification ] = await to(NotificationService.sendNotification(savedTask.assignedUser.id, 'Task was created for you'));
       if(err) return cb('Error while sending notification');
    }

    cb(null, savedTask);
}

async function asyncFunctionWithThrow() {
  const [err, user] = await to(UserModel.findById(1));
  if (!user) throw new Error('User not found');
  
}

TypeScript usage

interface ServerResponse {
  test: number;
}

const p = Promise.resolve({test: 123});

const [err, data] = await to<ServerResponse>(p);
console.log(data.test);

License

MIT © Dima Grossman && Tomer Barnea