Detailed explanation of the life cycle hook function in Vue3: Comprehensive mastery of the Vue3 life cycle

Vue.js is a popular front-end framework whose versions are constantly updated, and Vue3 is the latest version. In Vue3, life cycle hook function is one of the very important concepts. This article will introduce the life cycle hook function in Vue3 in detail, including what is the life cycle, the use of life cycle hook function, and what are the life cycle hook functions in Vue3.

What is life cycle?

In Vue3 applications, all components have their own life cycle. Life cycle refers to the entire process of a component from creation to destruction. During this process, the component will go through multiple states and stages, such as initialization, mounting, updating, and destruction. The main function of the life cycle hook function is to run code in these states and stages, and can perform different operations in different stages of the component.

Use of life cycle hook functions

The life cycle hook functions in Vue3 are divided into two categories: hook functions before and after component mounting and hook functions before and after component update. Among them, the hook functions before and after component mounting include:

1. beforeCreate: called before the component instance is created, when the component's data and methods have not been initialized;
2. created: Called after the component instance is created. At this time, the component's data and methods have been initialized, but the component has not yet been mounted on the DOM;
3. beforeMount : Called before the component is mounted. At this time, the component has completed compilation, but has not yet been mounted on the DOM;
4. mounted: Called after the component is mounted. This The component has been mounted on the DOM.

The hook functions before and after component update include:

1. beforeUpdate: called before the component is updated. At this time, the data of the component has changed, but The DOM has not been updated;
2. updated: Called after the component is updated. At this time, the data of the component has changed and the DOM has been updated;
3. beforeUnmount: Called before the component is unloaded, when the component still exists in the DOM;
4. unmounted: Called after the component is unloaded, when the component has been deleted from the DOM, all events Both listeners and timers have been cleared.

What are the life cycle hook functions in Vue3?

In addition to the life cycle hook functions mentioned above, Vue3 also provides the following life cycle hook functions:

1. activated: activated in the keep-alive component Called when;
2. deactivated: called when the keep-alive component is deactivated;
3. errorCaptured: called when a child component error is captured.

It should be noted that in Vue3, the two hook functions beforeDestroy and destroyed have been abandoned, and beforeUnmount# is used instead. ## and unmounted alternatives.

The execution order of hook functions

In Vue3, the execution order of life cycle hook functions is as follows:

1. beforeCreate
2. created
3. beforeMount
4. mounted
5. beforeUpdate
6. updated
##beforeUnmount
unmounted
8. ##In addition to the above hooks Outside the function,
activated

and

deactivated will only be triggered when using the keep-alive component; errorCaptured can be passed createApp() or app.component() method to register on the component. Summary

This article introduces the life cycle hook function in Vue3 in detail, including what is life cycle, the use of life cycle hook function, and what are the life cycle hook functions in Vue3. By fully understanding the life cycle hook functions of Vue3 and rationally using the life cycle hook functions, you can better control the life cycle of components and implement more complex interaction logic.

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