How to integrate PurgeCSS with Angular CLI project

Question

I have an Angular project created with Angular CLI, so I have angular.json file for configuring the build.

I wanted to integrate PurgeCSS as it seems to be a great tool

Answer 1

There is another way which is more in line with Angular CLI and Webpack config:

You need to install

npm install -D @angular-builders/custom-webpack postcss-scss @fullhuman/postcss-purgecss

Then create a webpack.config.js config file:

const purgecss = require('@fullhuman/postcss-purgecss')

module.exports = {
  module: {
    rules: [
      {
        test: /\.scss$/,
        loader: 'postcss-loader',
        options: {
          ident: 'postcss',
          syntax: 'postcss-scss',
          plugins: () => [
            require('postcss-import'),
            require('autoprefixer'),
            purgecss({
              content: ['./**/*.html'],
              // Example to let PurgeCss know how to exclude cdk and mat prefixes if your using Angular CDK and Angular Material
              whitelistPatterns: [/^cdk-|mat-/]
            })
          ]
        }
      }
    ]
  }
};

Then change your angular.json file to use this new configurations:

...
"build": {
  "builder": "@angular-builders/custom-webpack:browser",
  "options": {
    "customWebpackConfig": {
      "path": "webpack.config.js"
    },
    ...
  }
},
...

Make sure you run this configuration only in production mode, when you bundle the final application.

Hope this helps.

I created a post to explain how in detail - https://medium.com/@joao.a.edmundo/angular-cli-tailwindcss-purgecss-2853ef422c02