How to correctly use keep-alive components in vue projects

How to use keep-alive components correctly in Vue projects

In Vue projects, we often encounter situations where we need to cache components to improve user experience. Vue's keep-alive component was born for this. The keep-alive component can cache dynamic components or router-view components to maintain their state, reduce loading and rendering time, and improve page response speed.

Using the keep-alive component is very simple, just wrap the component that needs to be cached in the 7c9485ff8c3cba5ae9343ed63c2dc3f7 tag. So how do we use the keep-alive component correctly in a real project? Below are several examples to illustrate.

1. Caching dynamic components

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dc6dce4a544fdca2df29d5ac0ea9906b

<button @click="toggleComponent">切换组件</button>
<keep-alive>
  <component :is="componentName"></component>
</keep-alive>

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export default {
data() {

return {
  componentName: 'ComponentA',
};

},
methods: {

toggleComponent() {
  this.componentName = this.componentName === 'ComponentA' ? 'ComponentB' : 'ComponentA';
},

},
};
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In the above example, there are two dynamic components ComponentA and ComponentB. The displayed dynamic components can be switched by clicking the button. Use keep-alive components to wrap dynamic components to automatically implement caching and component state retention.

2. Cache router-view component

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<router-link to="/home">首页</router-link>
<router-link to="/about">关于我们</router-link>
<keep-alive>
  <router-view></router-view>
</keep-alive>

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< ;/template>

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export default {
...
};
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The above example is a Vue projects with routing functions can render corresponding components by clicking on different routing links. By wrapping the router-view component in a keep-alive tag, the components corresponding to each route can maintain their state when switching and avoid reloading.

It should be noted that since the keep-alive component caches all component instances, when the number of components is large, it will cause excessive memory usage, so the keep-alive component needs to be used appropriately.

At the same time, the keep-alive component also provides some properties and events, allowing us to use it more flexibly. The following are some commonly used properties and events:

• max: You can set the maximum number of cached components. When the number is exceeded, components that have not been used recently will be deleted.
• include: You can set to cache only components that meet the conditions, usually the component name or a regular expression.
• exclude: You can set not to cache components that meet the conditions. You can also use component names or regular expressions.
• activated: Event triggered when the cache is activated. You can handle the logic when the component is reactivated in this event.
• deactivated: Event triggered when the cache is deactivated. You can handle the logic when the component is deactivated in this event.

By using these properties and events appropriately, we can more flexibly control the behavior of keep-alive components and improve page performance and user experience.

To summarize, using the keep-alive component in a Vue project can easily achieve component caching and state retention. Through practical examples, we learned how to use the keep-alive component correctly, as well as the use of some properties and events. However, it should be noted that the keep-alive component needs to be used in appropriate places to avoid abuse and excessive memory usage. I hope this article will help you use keep-alive components in Vue projects.

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