How do I use computed properties in Vue.js?

How do I use computed properties in Vue.js?

Computed properties in Vue.js are used to define properties that depend on other data properties. They are cached based on their dependencies, meaning they only re-evaluate when one of their dependencies changes.

Can you give me an example of a computed property?

Sure! Here's a simple example: if you have a data property called firstName and another called lastName, you can create a computed property called fullName that concatenates them like this:

computed: {
  fullName() {
    return `${this.firstName} ${this.lastName}`;
  }
}

How do computed properties differ from methods?

Computed properties are cached based on their dependencies, while methods are re-evaluated every time they are called. Use computed properties for derived state and methods for actions.

When should I use computed properties instead of data?

Use computed properties when you need to derive a value from existing data properties. If the value is static or doesn't depend on other data, use data properties instead.