Why Do Arrow Functions Break Computed Properties in Vue.js?

Using Arrow Function in Computed Vue Properties

In Vue.js, handling data and logic in computed properties is crucial. However, utilizing arrow functions within these computed properties can result in unexpected behavior.

Originally, using traditional function declarations for computed properties worked as expected, as seen in this code snippet:

computed: {
  switchRed: function() {
    return { red: this.turnRed };
  },
  // ... other computed properties
}

However, switching to arrow functions in computed properties led to a problem where the color changes stopped working, even though the values were correctly updated.

computed: {
  switchRed: () => {
    return { red: this.turnRed };
  },
  // ... other computed properties
}

This issue arises because arrow functions do not bind the this context to the Vue instance for which the computed property is defined. Normally, computed properties bind this to the instance, allowing access to instance data and methods. However, with arrow functions, this retains the context of its parent, which is usually the global scope in JavaScript and not the Vue instance.

As a result, this.turnRed becomes undefined within the arrow function, causing the color change to fail. This behavior is documented in the Vue.js documentation, which advises against using arrow functions for instance properties or callbacks due to this reason.

To resolve this issue, revert back to using traditional function declarations for the computed properties, ensuring proper binding of this.

The above is the detailed content of Why Do Arrow Functions Break Computed Properties in Vue.js?. For more information, please follow other related articles on the PHP Chinese website!