what is computed property in vue js

Computed properties in Vue JS are properties that are generated dynamically based on other properties in the same component. They are like computed functions that reactively update whenever their dependencies change.

Computed properties are very useful in situations where you need to dynamically update the values of a component data property based on other properties in the same component. For example, you may have a component that needs to update its data property values based on the current time of the day.

In Vue JS, computed properties are declared as functions within the Vue instance. Whenever the function's dependencies change, the computed property will be updated with the new value.

For example, we can create a computed property that displays the current time of the day:

computed: {
  currentTime() {
    return new Date().toLocaleTimeString()
  }
}

Whenever the dependencies of the currentTime computed property change, such as the system clock, the value of the computed property will be automatically updated.

Computed properties are efficient when used correctly, as they are only updated when their dependencies change. This makes them a powerful tool for keeping data in sync with other properties in the component.