Code Splitting and Lazy Loading with Vite Quiz Quiz

Deepen your understanding of code splitting and lazy loading techniques in modern front-end projects using Vite. Evaluate best practices, benefits, and key implementation details relevant for optimizing application performance.

1. Dynamic Import Syntax

   Which syntax correctly enables code splitting for asynchronous modules using dynamic import in a Vite-powered project?

   1. load('./MyModule.js')
   2. require('./MyModule.js')
   3. import('./MyModule.js')
   4. fetch('./MyModule.js')

   Explanation: The correct answer is import('./MyModule.js'), which uses the dynamic import syntax enabling code splitting by loading modules only when needed. The require statement is synchronous and does not perform code splitting in modern build tools. load is not a recognized syntax for importing modules at all. fetch is used for network requests and cannot import JavaScript modules as code.

2. Advantage of Lazy Loading

   How does lazy loading modules affect the initial load time of a web application in practice?

   1. It typically reduces the initial load time by only loading critical code first.
   2. It increases the initial load time by delaying all scripts.
   3. It has no impact on initial load time, only on overall application speed.
   4. It causes all modules to download at once, using more bandwidth.

   Explanation: Lazy loading helps reduce the initial load time by deferring the download of non-essential modules until they are actually needed. Increasing the initial load time is incorrect because only critical scripts load immediately. The idea that it has no impact is false because deferring unnecessary code directly improves startup performance. Downloading all modules at once contradicts the concept of lazy loading.

3. Chunk Naming in Code Splitting

   Which approach allows you to assign a custom name to a code-split chunk in your application setup?

   1. Renaming the exported default function
   2. Placing the file in a folder named after the desired chunk name
   3. Adding a chunkName property to the import options
   4. Using a comment like /* webpackChunkName: 'myChunk' */ in the import statement

   Explanation: Custom chunk naming can be achieved by including a special comment such as /* webpackChunkName: 'myChunk' */ inside the dynamic import, guiding the bundler's output. Adding a chunkName property is not a valid import option. Placing the file in a specific folder or renaming the default export does not influence how the chunk is named. Only the special syntax in the comment is recognized for this configuration.

4. Identifying a Suitable Case

   In which scenario is it most appropriate to use lazy loading for a module in a modern web project?

   1. When the module is only required after a user completes an optional action
   2. When the module contains critical application logic used on every page
   3. When the module includes global styles that must load immediately
   4. When the module contains configuration that initializes the application

   Explanation: Lazy loading is most valuable for modules accessed during optional user actions, as this postpones their download until needed. Critical logic, global styles, and configuration modules should load upfront because delays could break the core experience. Deferred loading is only advantageous for modules that are not part of the immediate user workflow.

5. Potential Drawback of Excessive Splitting

   What is a key performance risk of splitting an application into too many small code chunks?

   1. The application will fail to compile due to splitting.
   2. Users will never be able to access non-critical features.
   3. All chunks will automatically merge and negate lazy loading benefits.
   4. Increased network requests can introduce overhead and slow down navigation.

   Explanation: Over-splitting leads to many HTTP requests which can add network latency, thus reducing overall performance. Chunks do not merge automatically; they stay split as designed. Access to non-critical features is unrelated to how many chunks exist. There is no compilation failure solely due to excessive chunking; it's a performance, not a build, issue.