vue.jsHow do I use the beforeUpdate hook in Vue.js?

The beforeUpdate hook in Vue.js is a function that is invoked before a component is updated. It is used to modify data, react to changes in data, or perform any other necessary operations before the component is re-rendered.

Example

<template>
  <div>
    <h1>{{ message }}</h1>
  </div>
</template>

<script>
  export default {
    data () {
      return {
        message: 'Hello World!'
      }
    },
    beforeUpdate () {
      this.message = 'Goodbye World!'
    }
  }
</script>

Output example

Goodbye World!

The code above contains an example of the beforeUpdate hook in action. The beforeUpdate function is defined inside the component's script tag and is used to modify the message data property. The message property is then rendered in the template tag with an h1 tag. When the component is updated, the beforeUpdate function is invoked, and the message property is changed from Hello World! to Goodbye World!, which is then rendered in the h1 tag.

The parts of the code above are as follows:

• <template>: This tag contains the HTML that is rendered when the component is mounted.
• <script>: This tag contains the JavaScript code for the component.
• export default: This is the keyword used to export the component.
• data(): This is a function that returns the data properties of the component.
• beforeUpdate(): This is the hook that is invoked before the component is updated.
• this.message: This is the data property that is being modified in the beforeUpdate hook.

Helpful links

• Vue.js Documentation - Lifecycle Hooks
• Vue.js Documentation - beforeUpdate

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