The difference between methods function and computed function in Vue documentation

In the Vue documentation, methods function and computed function are two functions that are used more frequently. Although the functions of these two functions are somewhat similar, their usage and application scenarios are obviously different. This article will introduce their differences in detail.

First of all, let us understand the meanings of methods function and computed function. The methods function is a method in the Vue instance. Its function is to define some event methods. These methods are generally used to respond to user interaction behaviors, such as click events, keyboard events, etc. The methods function can directly access the data in the Vue instance and operate on this data. The computed function is also a method in the Vue instance. Its function is to define calculated properties, that is, some values ​​that need to be dynamically calculated in the Vue instance. The computed function monitors data changes in the Vue instance. When these data change, the computed function automatically updates the corresponding calculated properties.

As can be seen from the above introduction, the difference between methods function and computed function mainly lies in two aspects: data source and execution timing. The data source of the methods function is the data in the Vue instance, while the data source of the computed function is other existing calculated properties or data in the Vue instance. In addition, the methods function is executed when user interaction is triggered, while the computed function is automatically executed when the data changes.

In specific application scenarios, the methods function is suitable for some scenarios that require dynamic response to user operations, such as click events, input box content changes, etc.; while the computed function is suitable for some values ​​that need to be calculated based on other data. , such as calculating the length of a list, calculating the difference between two data, etc. When you need to dynamically update the view, you should use the methods function; when you need to calculate a value and update the view, you should use the computed function.

In addition, it should be noted that when using the computed function, the calculated property must have a return value. Without a return value, a computed property cannot update the corresponding view. Moreover, you should try to avoid modifying the value of the data in the computed function, because this will cause the calculation results to be unstable, thus causing a series of problems.

In summary, although the methods function and the computed function are somewhat similar, their usage and application scenarios are obviously different. In specific applications, you should choose which function to use according to your needs in order to achieve better results.

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