What are computed properties in Vue's Options API?

What are computed properties in Vue's Options API?

Computed properties are reactive properties that depend on other data properties. They are defined in the 'computed' option of a Vue component.

Can you give me an example of how to use computed properties?

Sure! Here's a simple example:

export default {
  data() {
    return {
      firstName: 'John',
      lastName: 'Doe'
    };
  },
  computed: {
    fullName() {
      return `${this.firstName} ${this.lastName}`;
    }
  }
};

In this example, fullName is a computed property that combines firstName and lastName.

How do computed properties differ from methods?

Computed properties are cached based on their dependencies, meaning they only re-evaluate when their dependencies change. Methods, on the other hand, are executed every time they are called.

When should I use computed properties instead of methods?

Use computed properties when you need to derive a value based on reactive data and want to optimize performance. Use methods for actions that don't need caching.