What is the caching mechanism of keepalive in vue

The keep-alive caching mechanism in Vue includes: caching the state and DOM of specific subcomponents, optimizing performance and retaining dynamic data. Caching is triggered when a parent component renders for the first time, when a child component is manually activated, and when a cached component is activated again. Cache objects are stored inside keep-alive components, independent of Vue instance state. Invalidation mechanisms include re-rendering of parent components without sub-components, explicit destruction of sub-components, and cache limit. The benefits of caching include performance improvements, dynamic data retention, and smooth page transitions.

The caching mechanism of keep-alive in Vue

keep-alive is a component in Vue.js that allows a specific child component to maintain its state and activity when the parent component is re-rendered. The caching mechanism is as follows:

1. Cache object

In the keep-alive component, each cached sub-component has a The corresponding cache object. This object contains the following information about the child component:

• Component instance
• Component state (responsive data and methods)
• DOM rendered by the component

2. Caching timing

When a subcomponent is wrapped in keep-alive, it will be cached under the following circumstances:

• The first rendering of the parent component
• The child component is manually activated (use v-if or v-show to switch)

3. Cache storage

The cache object is stored in the internal state of the keep-alive component. This means that the state of the child component and the state of the DOM and Vue instance are separate.

4. Cache access

When the keep-alive component renders again and reactivates a cached child component, it will be retrieved from the cache Retrieve the cache object of this subcomponent from . It will then recreate the child component instance and use the cached object to restore its state and DOM.

5. Cache Invalidation

When the following occurs, the cached subcomponent will be invalidated and removed from the cache:

• The parent component is re-rendered and does not contain the child component
• The child component is explicitly destroyed
• keep-alive's max attribute is limited The maximum number of caches, and newly cached subcomponents will replace the oldest cache

Advantages

keep-alive's cache The mechanism provides the following advantages:

• Improves performance and avoids the overhead of re-creation and rendering by caching the state and DOM of child components.
• Preserve dynamic data, even if the parent component is re-rendered, the state and data in the child component can be maintained.
• Achieve smooth transition of page switching. By caching the status of components, you can avoid flickering and reloading when switching pages.

The above is the detailed content of What is the caching mechanism of keepalive in vue. For more information, please follow other related articles on the PHP Chinese website!