What does ionic serve executes in ionic 2? - ionic-framework

Question

I've been trying to add a gulp task to compile jade files I'm creating.
The tasks is working fine, however, when I run ionic serve it doesn't execute the gulp task I created
I assume that Ionic is using webpack, however I'd like to know what I need to do to make my new task work as well
The output I got is:
➜ ionic git:(master) ✗ ionic serve
∆ Compiling and bundling with Webpack...
√ Using your webpack.config.js file
∆ Compiling Sass to CSS
√ Matching patterns: app/theme/app.+(ios|md|wp).scss
∆ Copying fonts
√ Matching patterns: node_modules/ionic-angular/fonts/**/*.+(ttf|woff|woff2)
∆ Copying HTML
√ Matching patterns: app/**/*.html
√ HTML copied to www/build
√ Sass compilation complete

Answer 1

According to Ionic2 documentation regarding app-scripts, they have decided not to use gulp in their project any longer:
What About Gulp?
Historically Ionic apps have used gulp as tool to facilitate the build
process. Over the years, gulp has seen less and less development, and
has started to accumulate deprecation warnings. By taking advantage of
standard and dependency free NPM scripts, we are reducing dependencies
and simplifying the development experience.
Instead they are using Ionic app scripts, that are indeed npm scripts for their build process. From the same mentioned doc:
When ionic serve or ionic run are invoked, it ultimately calls an NPM
script. These npm scripts call the #ionic/app-scripts library to
execute the build process.
To accomplish your goal, i.e. to use Pug (formerly known as Jade) for the templates, you may do either of the following:
One: Write a custom app script instead of watch.config.js. The original script is available on here on github.
Two: Write a Cordova hook for before_compile.
As a reference this answer is written on 2016-Nov-12.