vue computed

Vue is a JavaScript framework that allows developers to build user interfaces. One of its key features is computed properties.

Computed properties in Vue are functions that are defined within a Vue instance or component. They are used to calculate and return a value based on other data properties.

When a computed property is defined, Vue automatically creates a dependency relationship between the computed property and the data properties it depends on.

This means that whenever any of the data properties change, Vue will automatically re-run the computed property function and update its value.

Computed properties are useful for performing complex calculations or transformations on data, without directly modifying the original data properties.

To define a computed property in Vue, you use the computed option within the Vue instance or component. You provide an object with key-value pairs, where the key is the name of the computed property and the value is the function that calculates the computed value.

The function can access other data properties using the this keyword, and it should return the computed value.

Once defined, you can access the computed property in your template or other parts of your code, just like a regular data property.

Vue caches the computed property value and only re-evaluates it when its dependencies change. This improves performance by avoiding unnecessary re-calculations.

Computed properties are reactive, which means that if any of its dependencies change, the computed property will automatically update its value.

Computed properties are also writable, which means you can use them in two-way data binding. You can assign a new value to a computed property, and it will update its dependencies accordingly.

Computed properties are a powerful feature in Vue that help keep your code clean and organized by separating the data logic from the presentation logic. They are especially useful when you need to perform complex calculations or transformations on your data.