Common props default value trap problems in Vue components

1. Issues of sharing default values ​​of objects and arrays

When you take an object or array as the default value for props, they are shared among all instances of the component. This means that if one component changes this default value, other components will be affected as they share the same reference.

trap:

props: {
  userInfo: {
    type: Object,
    default: {}
  }
}

question:If a component is modifieduserInfo Objects, other instances using the same component are also affected.

Solution:Use a function to return a new object to ensure that each component has its own independent object.

props: {
  userInfo: {
    type: Object,
    default: function () {
      return {};
    }
  }
}

2. Default value type issue for non-primitive values

Vue'sprops The default value type needs to be the original value, such as strings, numbers, boolean values, etc. Vue may raise a warning if you try to use a non-primitive value as the default value type.

trap:

props: {
  items: {
    type: Array,
    default: []  // Default value type for non-primitive values  }
}

question:The default value type should be the original value, not the reference type.

Solution:Create a function or computed property inside the component to return the default value of the non-primitive value.

props: {
  items: {
    type: Array,
    default: function () {
      return [];
    }
  }
}

3. Responsiveness issues when using default values

The default value of props is only set once when component instance is created. If the default value is subsequently changed, re-rendering of the component will not be triggered. This may cause the component to not respond to subsequent changes correctly.

trap:

props: {
  count: {
    type: Number,
    default: 0
  }
}

question:If subsequent changes arecount The default value of the component will not be rerendered.

Solution:If you need to re-render the component after the default value changes, use computed properties or observers to monitorprops Changes.

props: {
  count: {
    type: Number,
    default: 0
  }
},
computed: {
  updatedCount() {
    return ; // Use Computing Properties  }
}

4. The default value does not match the verification type

If the default value does not match the verification type, Vue will not issue a warning, but may still lead to unexpected behavior.

trap:

props: {
  age: {
    type: Number,
    default: '25' // The default value does not match the verification type  }
}

question:A default value does not match the verification type may result in type errors and inconsistent data.

Solution:Make sure that the default value type matches the verification type.

props: {
  age: {
    type: Number,
    default: 25 // The default value matches the verification type  }
}

This is the end of this article about avoiding the common props default value traps in Vue components. For more related vue props default value content, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!