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In Vue , when a child component changes the data in props, it will cause the responsiveness of the parent component and other child components to change.

First, you need to understand that props is a way to pass data from a parent component to a child component. After defining props in a component, the parent component can pass data to the child component through these props. The child component receives these props and can use the data inside the component.

However, changing the data in props in a child component will result in the following two situations:

1. The data in the parent component is also changed
2. Vue throws an error, saying that the value of props cannot be modified

This is because props in Vue are one-way data flow and can only be passed from parent components to child components. Child components should avoid directly changing the data in props because it will affect the responsiveness of other components.

For example, suppose there is a shopping cart component and a product list component. The product list component receives the product information in the shopping cart component through props. If the quantity of the product is changed in some way in the product list component, this will affect the quantity of the product in the shopping cart component.

The solution to this problem is to use a calculated property or method in the product list component to return a new value. For example, in the above example, the product count is increased by calling the increment method. This can better update the number of items in the shopping cart without affecting the responsiveness of other components.

In addition, Vue also provides a developer tool to help detect errors that should not modify props. Developers can find it in the browser console and avoid modifying the data in props.

In short, in Vue, child components should avoid directly changing the data in props to avoid unnecessary errors and problems. If necessary, use calculated properties or methods to create a new value.

However, in some cases, the child component needs to modify the data passed in. At this time, we can use the sync modifier or v-model in Vue's prop to achieve this goal.

The benefit of using syncmodifiers or v-modelis that you can avoid some problems that occur when directly changing the data in props. For example, when using the sync modifier or v-model, Vue actually uses a temporary variable to temporarily store the value, and then passes this temporary variable to the child component. This means that when the child component operates on this value, it will only change the temporary variable, and will not change the actual data in the parent component.

Here is an example using v-model:

<template>
  <div>
    <input v-model="value" />
    <ChildComponent v-model="value" />
  </div>
</template>

<script>
import ChildComponent from './ChildComponent.vue';

export default {
  components: {
    ChildComponent
  },
  data() {
    return {
      value: ''
    };
  }
};
</script>

In the above example, we pass value to ChildComponentthe component and use v-modelto associate value with the value in the child component. This means that when you modify the value in the child component, you are actually modifying the value in the child component instead of the parent component. This ensures one-way data flow and avoids some potential problems.

In summary, in Vue , it is not recommended to change the data in props directly. You can use syncmodifiers or v-modelto change the data, and this can ensure the one-way flow of data and avoid potential problems.