Learning Node.js Development

Introduction to ES6 promises

Promises aim to solve a lot of the problems that come up when we have a lot of asynchronous code in our application. They make it a lot easier to manage our asynchronous computations—things such as requesting data from a database. Alternatively, in the case of a weather app, things such as fetching data from a URL.

In the app.js file we do a similar thing using callbacks:

const yargs = require('yargs');const geocode = require('./geocode/geocode');const weather = require('./weather/weather');const argv = yargs  .options({    a: {      demand: true,      alias: 'address',      describe: 'Address to fetch weather for',      string: true    }  })  .help()  .alias('help', 'h')  .argv;geocode.geocodeAddress(argv.address, (errorMessage, results) => ...