Unlock Efficient Vue.js Development: Mastering Lazy Loading
What is Vue.js?
Vue.js is a progressive JavaScript framework created by Evan You and the Vue core team, with contributions from over 230 open source community members. With over 183,000 stars on GitHub, Vue.js consists of an approachable core library that focuses on the view layer only, accompanied by an ecosystem of supporting libraries designed to tackle complexity in large single-page applications.
Lazy Loading: The Key to Efficient Development
Lazy loading is a pattern designed to delay the initialization of elements and objects until they are needed. This approach ensures that a target DOM element, relative to a parent DOM element, is loaded and becomes visible only when a user scrolls through them on a webpage. To understand lazy loading, it’s essential to first grasp eager loading, the default approach to loading JavaScript code onto the DOM.
Why Lazy Loading Matters
As your Vue.js project grows in size and complexity, eager loading can lead to a cumbersome JavaScript bundle, causing issues for end-users accessing your application on mobile devices or with slow internet connections. Lazy loading guarantees that your JavaScript bundle is fed to the DOM in an order of importance, ensuring control over the entire user experience, including the initial wait period when resources are loaded onto the DOM.
A Practical Vue.js Lazy Loading Example
Let’s build an example Vue.js app with the Vue CLI and add routing during the configuration stage. We’ll also add a third route manually to demonstrate the process for developers unfamiliar with the Vue CLI.
Starting a Vue.js Project
Create a new project with the Vue CLI, selecting the router option and storing all configs in the package.json file. Once the project is created, change the directory to the new project folder and run the application in the development environment.
Manually Adding a New Route
Add a third view and register a route for it. Create a new file, extra.vue, and copy the contents of the about.vue file into it. Then, open the router.js file and add the extra code block under the routes array.
Lazily Loading Vue.js Components
Configure all routes to be lazily loaded on request. Open the router.js file and remove import statements, creating a lazyLoad function to make the import statement clean. Embed the webpack import statement into the routes section instead of the import section at the start of the script.
Testing the Loading Strategy
Run the application again in development, opening it up at http://localhost:8080/ in your browser and inspecting the network section and JS tab in developer tools. Verify that the lazy loading worked by building out the application for production.
Efficient Development with Lazy Loading
Lazy loading might not be crucial in small Vue.js projects, but as your project grows complex, it becomes essential to implement lazy loading in your workflow for efficiency and optimal resource usage. Experience your Vue apps exactly how a user does with LogRocket, the DVR for web and mobile apps, recording everything that happens in your Vue apps.