A little automation

Running node src/index.js every time I want to see the effect of a change quickly becomes annoying. Let's make this automatic, and also reload the page in the browser while we're at it!

For that, I'll rely on two widely used projects, rather than the metalsmith-watch plugin, which looked a bit too dormant to me:

Let's dive in!

Automating the site generation

nodemon takes care of watching files and re-running the code of a NodeJS (or even in another other language) project when they change. As it will only be used for development, let's install it with the --save-dev/-D flag:

npm i -D nodemon

Out of the box, without any parameter npx nodemon runs the file set in the "main" field of package.json. Let's make sure we got it right and set it to src/index.js (this will also enable to generate the site with only node .).

For now, the site will only rebuild when changing JavaScript or JSON files (the default Nodemon behaviour). Thing is, we'll want it to rebuild when the content changes, or the layout, or later when changing the stylesheets. This can be configured in a nodemon.json file at the root of the project. While there, we can also set it to ignore the site folder to avoid ending in an infinite loop of rebuilding.

  "ext": "js,pug,md,json,css",
  "ignore": [

That should cover most of the changes for now.


Now the site gets built automatically, let's see how to reload the page automatically with browser-sync. Just like nodemon, it's a development dependency so let's install it with the -D flag:

npm i -D browser-sync

To check that everything is installed OK, we can have it serve the site folder with:

npx browser-sync start -s site

This should open a browser window on http://localhost:3000 (if the 3000 port not free, BrowserSync will let you know which port it uses in the console).

With the previous command, BrowserSync only serves the site. Its reloading feature need to be enabled with the -w flag:

npx browser-sync start -s site -w

Everytime the files in the site folder change now, BrowserSync should reload the browser.

Co-ordinating Nodemon and Browsersync

Unfortunately, more than once the reloading didn't happen for me, so I had to look at another way.

BrowserSync offers another way to reload the pages. An HTTP request to /__browser_sync__?method=reload will trigger a reload. On its side, Nodemon allows to run scripts when specific events happen, like when the project exits cleanly. This'll be perfect for making that call to BrowserSync.

Inside the nodemon.json configuration, we can make the two tools work together:

  "events": {
    "exit": "curl -s http://localhost:3000/__browser_sync__?method=reload > /dev/null && echo 'Restarted browser-sync' || echo 'Failed to restart broswer-sync'"

A little cleaning up of the output with the > /dev/null, some nicer feedback with a couple of echo triggered when the request works (&&) or fails (||) and the reload was much more reliable for me (though a little slower).

Running both commands together

Most often, they'll be run alongside each other as I work on the project. The concurrently package will allow to start them in a single command. Even better, it allows to keep typing rs to Nodemon for restarting manually if needed.

npm i -D concurrently

Once installed, a couple of scripts in the package.json will launch everything with a single npm run dev. concurrently will run all the tasks starting with dev:, allowing future tasks to be easily added. And the input will be specifically redirected to dev:watch corresponding to Nodemon.

"script": {
  "dev": "concurrently --handle-input --default-input-target dev:watch 'npm:dev:*'",
  "dev:watch": "nodemon",
  "dev:serve": "browser-sync start -s site --no-open",

All set and ready to (finally) start building the internationalisation features... which was the initial aim.