First steps with webpack, babel, and yarn

Passata is being rewritten at the moment so the information in this page is out of date. I’ll be publishing a new article as soon as it’s ready.

I have just started my journey in the React ecosystem. I decided to take notes along the way so I could share my experience with you. Most of the resources I found focus on the coding experience: how to test, how to integrate React with X and so on. I, on the other hand, tend to focus on:

  • Available documentation
  • Error messages when I make mistakes
  • How to ship an application written in X to production
  • What does the community look like? Is it inclusive? Is it active? Is it welcoming to newcomers?

Furthermore, I knew nothing at all about React when I started my journey, which makes me an experienced newcomer: I have been working in the industry for more than a decade but I know nothing about React.

What I want to learn #

Here is the list of technologies I intend to explore:

As I knew nothing about any of the technologies I listed, I decided to build a small application to support me with the pomodoro technique. I intend to adopt React for a larger application soon, and a small application I can use everyday is a fun way to understand if I’m heading in the right direction.

Overwhelming setup #

I started with a React “hello world”:

import React from "react";
import ReactDOM from "react-dom";

ReactDOM.render(<h1>Hello World!</h1>, document.getElementById("root"));
    <div id="root"></div>
    <script src="/App.js" type="text/javascript"></script>

It’s just a few lines of code but I felt overwhelmed: there’s so much going on. I read React installation guide and I understood I needed webpack and babel. I ran into yarn and it looked great, so I decided to add one more item to my list. I read up on docs a bit more, tried some commands locally and felt discouraged.

I had to learn upfront so many things to run a hello world program that I started looking for help. I tried create-react-app and I got this nice “it just works” feeling. I could have started with React components right away, but I care too much about how X works rather than just coding with X. I can’t use technology as a closed box and carry on with my little application. It was late in the evening that day so I decided to start over the day after and went to bed.

I started over twice: the first time I realised I did not want to use create-react-app; then I decided to take notes so I could write the article you are reading.

Here are the first commands I typed:

mkdir passata
cd passata
git init
yarn init

I felt good about yarn. Its output is helpful and the UI is intuitive. And it is fast, really fast.

Hello world #

I moved on to create my first React application. It wasn’t working and that was a conscious strategy: one tiny step at the time so I could understand all the tooling involved. I needed react and react-dom and I added them as dependencies. I enjoyed yarn’s output one more time: in the commit message you can see how nice some details of this tool are. Yarn reported there was no lock info file. It informed me, but it didn’t block the process. Instead, it went ahead and created the lock file for me. I think that’s good user experience for a developer.

Since the hello world code I wrote uses ES6, I needed to bring Babel in right after the obvious dependencies were met. I had no idea what Babel was and what it did, so I checked the website to understand the basics. And that was the first roadblock of my tiny project: the home page says nothing about how to get started with it. It has two big CTAs:

  • Setup: There are thirty seven buttons on the page and I knew nothing about most of the them. I knew I needed webpack so I clicked that one. That brought up some incredibly minimal documentation.
  • Trying it out: I get it, it does cool stuff. I still didn’t get how to use it and where to start, though.

I kept reading the documentation on the website and found “presets”. I understood I needed some of them but I did not know why, so I went for “let’s try things out and see if they work”. I moved on to webpack thinking I needed to use it to run Babel anyway. I wasn’t really sure though and it did not feel great.

I spent a while reading webpack documentation. The concepts section is great for people that have no idea how the tool works. I read the entire section and realised that:

I configured them here. I added a “scripts” section to the package.json in the same commit as the documentation explains here. This way I could use yarn as a task runner and skip the creation of a Makefile at the moment.

The application was still not working though, as you can see here. Babel wasn’t doing anything because it wasn’t configured. Somehow I felt I needed presets (no one had explained to me before what they were, though). I assumed I needed two:

  • es2015
  • react

I couldn’t figure out if the order was relevant and, if so, what the right order to add presets was. For the first time since I had started, I had to search the web. I ran into a nice blog post and decided to trust the order of the presets mentioned in the article. I added the configuration but the result was confusing me. Babel seemed to work on its own; compiling the App.js file with it produced the right output. But it was still not working when run via webpack.

It works! #

I made it work here. It took me some time to understand why it wasn’t working. I had made a mistake a few commits before and fixing it was tricky: I had the wrong version of webpack in my yarn.lock. I am not sure why yarn picked a 1.x version for webpack. I thought the reason was that 2.x version had been released a few days before. Once I got the right version, I could correct another little mistake in the configuration and then finally build my first React application.

It took only a few hours and it was great experience. The most important learning was: documentation is vital and it’s hard to write. And it’s even harder to write documentation for newcomers. In this regard, React' documentation is great. I needed only the installation guide to get things work and I knew nothing about React when I started. Webpack 2 docs are good too. It’s great they take quite some time to explain the main concepts. I cannot say the same about Babel, the experience with the documentation has been very frustrating so far.

What’s next? #

I have a lot of questions:

  • What’s a good way to run a React application in development mode? I’ve read somewhere there’s a webpack plugin (are they called plugins?).
  • What about css and images? I guess I want webpack to take care of assets too. Should I do something special about bootstrap if I want to use it?
  • How do I layout the project’s folders? Is there any convention for React applications?

Thank you for reading and stay tuned for the next article in the series!