By default, Ionic only enable sourcemap for .ts
file and disable for .sass
(https://github.com/driftyco/ionic-app-scripts/blob/master/config/sass.config.js#L16).
So, if you want to enable and debug your stylesheets file, just follow 2 steps:
Create config/sass.config.js
module.exports = {
sourceMap: true,
}
Update package.json
"config": {
"ionic_sass": "./config/sass.config.js",
},
And just re-run ionic serve
command.