matthewgsommers / optimizing-web-apps-webpack

Code samples for my webpack course series

Course Details

• Initial code
• Final code

Tentative webpack course series:

1. (publishing soon) Webpack: Transpiling and Bundling JavaScript
2. (tentative) Webpack: Beyond JavaScript
3. (tentative) Webpack: Bundle Optimization

Tentative means not set in stone.

• Course #1 uses webpack v3. Tentatively there will be a guide about upgrading from webpack v3 to v4 in Course #2.
• Course #2 and #3 will be created after webpack v4 RTM.
• Course #1 is bundling and transpiling JavaScript.
• Course #2 is bundling and transpiling/compiling everything else in a front end app: styles, layouts, images, webassembly, etc.
• Course #3 is then about optimizing the bundles!

Errata / Updates

Check here for notes about updates to webpack that are related to materials covered in the course series

• webpack v4 (based on latest alpha.5)
  • Nothing has fundamentally changed in webpack v4 that obviates what was covered in Course #1.
  • CLI extracted to new webpack-cli package
    • Just npm install webpack-cli instead of npm install webpack
    • webpack package will only provide the API
    • See redirection in webpack package's bin\webpack.js
  • entry defaults to ./src
  • output.path defaults to absolute path to ./dist
  • New, required mode config adds common optimization plugins
    • This is simply a new configuration style!
    • Matching --mode CLI argument
    • Intended to be production or development to optimize accordingly
    • Coarse mode maps to new, granular optimization.* settings. Most of these are flags to enable/disable a plugin.
      • See mode => optimization.* mapping in WebpackOptionsDefaulter.js (search for mode)
      • See optimization.* => plugins mapping in WebpackOptionsApply.js (search for optimization)
    • To use webpack v4 with Course #1 set mode: "none" to disable this new configuration style.
      • All you're doing is turning off some webpack features, notably bundle optimization. Doing this is helpful to learn what is going on under the hood. You can incrementally add back optimizations and look at the bundle impact one at a time.
      • This is likely how I will teach going forward even with v4.
    • Most of the optimization plugins won't be covered until Course #3 so this is largely irrelevant. The following new flags relate to topics covered in Course #1 if mode == 'development':
      • optimization.namedModules adds NamedModulesPlugin
      • devtool defaults to eval
      • output.pathinfo defaults to true
    • This new mode compliments techniques shown in Course #1's Dev Isn't Prod module.