- The Vue Instance
- Template Syntax
- Computed Properties and Watchers
- Class and Style Bindings
- Conditional Rendering
- List Rendering
- Event Handling
- Form Input Bindings
- Components Basics
- Component Registration
- Custom Events
- Dynamic & Async Components
- Handling Edge Cases
Transitions & Animation
- Enter/Leave & List Transitions
- State Transitions
Reusability & Composition
- Custom Directives
- Render Functions & JSX
- Single File Components
- TypeScript Support
- Production Deployment
- State Management
- Server-Side Rendering
- Reactivity in Depth
- Migration from Vue 1.x
- Migration from Vue Router 0.7.x
- Migration from Vuex 0.6.x to 1.0
- Migration to Vue 2.7
- Comparison with Other Frameworks
- Join the Vue.js Community!
- Meet the Team
Dynamic & Async Components
This page assumes you’ve already read the Components Basics. Read that first if you are new to components.
Earlier, we used the
is attribute to switch between components in a tabbed interface:
When switching between these components though, you’ll sometimes want to maintain their state or avoid re-rendering for performance reasons. For example, when expanding our tabbed interface a little:
You’ll notice that if you select a post, switch to the Archive tab, then switch back to Posts, it’s no longer showing the post you selected. That’s because each time you switch to a new tab, Vue creates a new instance of the
Recreating dynamic components is normally useful behavior, but in this case, we’d really like those tab component instances to be cached once they’re created for the first time. To solve this problem, we can wrap our dynamic component with a
Check out the result below:
Now the Posts tab maintains its state (the selected post) even when it’s not rendered. See this example for the complete code.
<keep-alive> requires the components being switched between to all have names, either using the
name option on a component, or through local/global registration.
Check out more details on
<keep-alive> in the API reference.
In large applications, we may need to divide the app into smaller chunks and only load a component from the server when it’s needed. To make that easier, Vue allows you to define your component as a factory function that asynchronously resolves your component definition. Vue will only trigger the factory function when the component needs to be rendered and will cache the result for future re-renders. For example:
As you can see, the factory function receives a
resolve callback, which should be called when you have retrieved your component definition from the server. You can also call
reject(reason) to indicate the load has failed. The
setTimeout here is for demonstration; how to retrieve the component is up to you. One recommended approach is to use async components together with Webpack’s code-splitting feature:
You can also return a
Promise in the factory function, so with Webpack 2 and ES2015 syntax you can make use of dynamic imports:
When using local registration, you can also directly provide a function that returns a
If you’re a Browserify user that would like to use async components, its creator has unfortunately made it clear that async loading “is not something that Browserify will ever support.” Officially, at least. The Browserify community has found some workarounds, which may be helpful for existing and complex applications. For all other scenarios, we recommend using Webpack for built-in, first-class async support.
New in 2.3.0+
The async component factory can also return an object of the following format:
Note that you must use Vue Router 2.4.0+ if you wish to use the above syntax for route components.