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:

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

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.

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