How to use Vue's keep-alive component to optimize page rendering performance

How to use Vue’s keep-alive component to optimize page rendering performance

With the development of front-end development, single page applications (SPA) are becoming more and more common in web applications. However, the subsequent problem is the rendering performance of the page, especially when large-scale data changes or frequent page switching will lead to performance degradation. Vue's keep-alive component provides an optimization solution that can significantly improve page rendering performance. This article will introduce how to use Vue's keep-alive component to optimize the rendering performance of the page, and demonstrate it through code examples.

1. The role of keep-alive component

Vue’s keep-alive component can cache components into memory. When components are switched, they will not be re-rendered, but will be taken directly from memory. Components that have been rendered. This can greatly improve the rendering performance of the page and reduce unnecessary performance consumption. At the same time, the keep-alive component also provides two life cycle hook functions, activated and deactivated, which can perform certain operations when the component is activated and deactivated.

2. Use the keep-alive component

When using the keep-alive component, you need to wrap the component that needs to be cached in the 7c9485ff8c3cba5ae9343ed63c2dc3f7 tag and set a unique attribute Values ​​used to identify different components. For example:

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<keep-alive>
  <router-view :key="$route.fullPath"></router-view>
</keep-alive>

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In this example, We dynamically switch and cache components by setting the :key attribute value of 975b587bf85a482ea10b0a28848e78a4 to $route.fullPath. When the route changes, the keep-alive component will determine whether the component needs to be re-rendered based on the :key change.

3. The life cycle of the cache component

When using the keep-alive component, you need to pay attention to the life cycle of the cache component. When a component is cached, its life cycle will undergo some changes. Specifically, the two life cycle hook functions activated and deactivated will be executed when the component is activated and deactivated.

For example, we can obtain the data of the activated component in the activated hook function and perform some initialization operations. And in the deactivated hook function, we can save the component's state so that it can be restored upon reactivation.

The following is a sample code:

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<h2>{{ message }}</h2>

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export default {
data() {

return {
  message: 'Hello World'
};

},
activated() {

this.message = 'Component activated';
// 执行其他操作

},
deactivated() {

// 保存组件状态

}
};
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In this example, when this component is cached, it will be displayed each time it is activated. Component activated", and each time it is deactivated, the state of the component can be saved in the deactivated hook function.

4. Avoid caching without using keep-alive components

Although keep-alive components can improve the rendering performance of the page, not all components are suitable for caching. Some components need to update data every time they are re-rendered, so using keep-alive components in these components can lead to incorrect data or unexpected results.

Therefore, for those components that do not require caching, we can exclude caching by setting the exclude attribute. For example:

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<keep-alive exclude="ComponentB">
  <ComponentA></ComponentA>
</keep-alive>
<ComponentB></ComponentB>

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In this example, ComponentA will be cached, but ComponentB will not be cached.

Summary:

Vue’s keep-alive component is a powerful performance optimization tool that can greatly improve the rendering performance of the page. By caching components in memory, unnecessary re-rendering can be avoided. At the same time, two life cycle hook functions, activated and deactivated, are provided to meet some needs that require specific operations to be performed when components are activated and deactivated. However, it should be noted that not all components are suitable for caching. For those components that need to be re-rendered each time, keep-alive components should be avoided. By rationally using the keep-alive component, you can improve the rendering performance of the page and enhance the user experience.

The above is an introduction and sample code on how to use Vue’s keep-alive component to optimize page rendering performance. Hope this article is helpful to you.

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