Vue component communication: how to pass data through props?

Vue component communication: How to pass data through props?

In Vue development, component communication is an important task. Vue provides a variety of ways to communicate between components, one of the most common ways is to pass data through props attributes. This article will introduce how to use props to pass data and provide relevant code examples.

1. What are props?
   props is a property in the Vue component system, used to receive data passed by the parent component. Parent components can define props attributes in child components and pass data to child components through props. Child components can use these props data for rendering and manipulation.
2. How to define props?
   In child components, props attributes can be defined through the props option. The props option can be a string array or an object. If it is a string array, it means receiving these properties passed by the parent component. If it is an object, it means further defining the types and default values ​​of these properties.

The following is an example showing how to define the props attribute:

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

<script>
export default {
  props: {
    message: {
      type: String,
      default: 'Hello, props!'
    }
  }
}
</script>

In the above code, the subcomponent defines a props attribute named message, The type is String and the default value is 'Hello, props!'. Parent components can pass data to child components through this property.

3. How to pass props?
   In the parent component, you can use the tag of the child component and assign a value to the props attribute to pass data. For example:

<template>
  <div>
    <child-component :message="parentMessage"></child-component>
  </div>
</template>

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

export default {
  components: {
    ChildComponent
  },
  data() {
    return {
      parentMessage: 'Hello, parent!'
    }
  }
}
</script>

In the above code, the parent component passes the value of parentMessage to the child component through the message attribute. Note that when passing properties, use a colon (:) to indicate that the property is dynamic, not a string.

4. How to use props in child components?
   In child components, you can directly use the value of the props attribute. For example:

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

<script>
export default {
  props: ['message']
}
</script>

In the above code, the child component is rendered directly using the value of the message attribute.

5. How to verify the type of props?
   In child components, you can verify whether the passed values ​​are as expected by defining the type of props. For example:

<template>
  <div>
    <span>{{ count }}</span>
  </div>
</template>

<script>
export default {
  props: {
    count: {
      type: Number,
      required: true
    }
  }
}
</script>

In the above code, the subcomponent defines a props attribute named count, which is of type Number and is required. If the parent component does not pass the count attribute or the value type passed is not Number when using the child component, the console will output a warning message.

6. How to set the default value of props?
   In child components, you can use the default attribute to set the default value of props. For example:

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

<script>
export default {
  props: {
    message: {
      type: String,
      default: 'Hello, props!'
    }
  }
}
</script>

In the above code, the default value of the message property of the subcomponent is 'Hello, props!'. If the parent component does not pass the message attribute when using the child component, the child component will use the default value for rendering.

The above are related operations and code examples of using props to transfer data. Through props, we can easily pass data between different components and achieve communication between components. Props can not only pass basic types of data, but also complex objects or arrays, providing more flexibility and functionality.

Summary:

• props is a way to pass data in Vue component communication;
• Use the props option in sub-components to define props attributes;
• Use the label of the subcomponent in the parent component and assign a value to the props attribute to pass the data;
• You can directly use the value of the props attribute in the subcomponent;
• You can set props The type and default value to validate and set the passed properties.

I hope this article will help you understand and use props attributes in Vue component communication!

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