The role of created in vue

The role of the created() life cycle hook in Vue.js is to obtain resources, such as obtaining data from a remote server or local storage. Initialize component state, such as setting default values ​​or getting state from an external source. Set up observers to listen for state changes or external events. Update the DOM in special cases, such as inserting HTML fragments.

The role of created() life cycle hook in Vue.js

created() is Vue.js A lifecycle hook that is called before the component is instantiated and mounted.

Function:

created() hook is mainly used for the following purposes:

• Resource acquisition: Here The data required by the component can be obtained from the remote server, local storage or other data sources in the hook.
• State initialization: Can be used to initialize the internal state of the component, such as the default value or the state obtained from an external data source.
• Set observers: You can set up observers to listen for changes in component status or external events.
• Update DOM: Although updating the DOM directly in the created() hook is not recommended, it can be used in some special cases, such as manually inserting HTML fragments.

Usage example:

import { ref, onMounted, created } from "vue";

export default {
  created() {
    const userData = ref(null);

    // 获取用户数据并将其保存在 userData 中
    fetchData().then((response) => {
      userData.value = response.data;
    });
  },
  mounted() {
    // 在 DOM 挂载后使用userData
  },
};

Note:

• created() hook is rendered on the server side (SSR) will not be called during.
• The created() hook is called before the beforeMount() hook and the DOM cannot be accessed in this hook.
• The created() hook does not receive any parameters.

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