How to use computed in vue

Computed computed properties in Vue.js are functions that calculate and return derived values. They are used to: Calculate values ​​based on other reactive data. Use reactive functions to access other reactive properties or components. Reactive: Automatically updates to reflect changes in dependent properties. Efficient: only recalculate when dependent properties change. Reusable: can be reused by other components or computed.

Computed computed properties in Vue.js

What is computed in Vue.js?

Computed is a computed property in Vue.js that is used to calculate and return a derived value based on other reactive data. It is essentially a function that can be accessed by other reactive properties or components.

How to use computed?

To use computed, you need to define a function in the computed option of the Vue instance, as shown below:

const app = new Vue({
  computed: {
    fullName() {
      return `${this.firstName} ${this.lastName}`;
    }
  },
  data() {
    return {
      firstName: "John",
      lastName: "Smith"
    };
  }
});

In the above example, fullName is a computed that uses the firstName and lastName data properties to compute and return a full name ("John Smith").

Advantages of computed:

• Responsive: computed will automatically update when the dependent reactive properties change.
• Efficient: computed will only be recalculated when the dependent properties change.
• Reusable: computed can be reused by other components or computed, thus simplifying the code.

Notes on computed:

• computed cannot have side effects, such as modifying responsive data.
• computed should be kept as simple and efficient as possible. Complex calculations should consider using methods or services.
• Computed dependent properties must be responsive. If the dependent property is non-reactive, computed will not be updated.

The above is the detailed content of How to use computed in vue. For more information, please follow other related articles on the PHP Chinese website!