Webpack Performance Optimization Techniques Quiz Quiz

Challenge your understanding of key Webpack performance optimization techniques with focused questions on code splitting, caching strategies, bundle analysis, and more. Enhance your skills in improving build times and output efficiency using proven Webpack methods and best practices.

1. Code Splitting Fundamentals

   Which Webpack feature allows you to split your application into smaller chunks, such as separating vendor libraries from your main code bundle?

   1. Chunk Minimizing
   2. Hot Module Replacement
   3. Tree Shaking
   4. Code Splitting

   Explanation: Code Splitting in Webpack enables you to divide your codebase into smaller bundles or chunks, which can be loaded on demand and improve performance by reducing initial load times. Tree Shaking removes unused code but does not handle splitting. Hot Module Replacement is for updating modules in development without a full reload. Chunk Minimizing is not a standard Webpack optimization feature.

2. Optimizing Caching

   What is the primary benefit of adding content hashes to output filenames in a Webpack configuration, such as 'bundle.[contenthash].js'?

   1. Improves browser caching by generating unique file names when content changes
   2. Prevents all forms of code duplication
   3. Automatically minifies all JavaScript files
   4. Increases file size to enhance compression efficiency

   Explanation: Using content hashes in output filenames lets browsers identify when files have changed, enabling efficient caching because unchanged bundles retain their original names and can be pulled from cache. Increasing file size is not a benefit of hashing; it ideally has no effect. Minification is a separate process not related to filename hashes. Content hashes do not prevent code duplication but aid in cache invalidation.

3. Analyzing Bundle Size

   If your Webpack output bundle is unexpectedly large, which built-in feature or tool is best to identify the largest modules or dependencies in your bundle?

   1. Polyfill Injector
   2. Bundle Analyzer
   3. Module Hot Loader
   4. Tree Shaker

   Explanation: Bundle Analyzer provides a visualization of your output bundle so you can see which modules or dependencies make up the bulk of the size, helping you find optimization opportunities. Module Hot Loader is for efficient development workflows. Tree Shaker removes unused exports but does not visualize bundle size. Polyfill Injector is not a core tool for analyzing bundle size.

4. Tree Shaking Efficiency

   How does enabling Tree Shaking in Webpack impact your production bundles when your source code uses ES Module syntax?

   1. Disables all dynamic imports
   2. Automatically compresses all images in assets
   3. Adds support for legacy browsers automatically
   4. Removes unused exports from the final bundle, reducing size

   Explanation: Tree Shaking operates on ES Module syntax to identify and eliminate code that is not actually used in the final bundle, making the bundle smaller and more efficient. It does not compress images; image optimization is a different concern. Tree Shaking does not handle browser support or polyfills, nor does it disable dynamic features like imports.

5. Production Mode Benefits

   What happens when you set Webpack's mode to 'production' during your final build?

   1. Forces the build to run in strict development mode
   2. Disables all loaders and plugins in the configuration
   3. Removes all source maps from the build, making debugging impossible
   4. Webpack enables optimizations such as minification and sets process variables for minimized output

   Explanation: Setting Webpack's mode to 'production' triggers various performance optimizations by default, including enabling minification and adjusting process variables for performance. It does not disable loaders or plugins—they still work as configured. The production mode does not enforce development settings. Source maps are not forcibly removed; developers can still generate them if configured.