Filter function in Vue3: handle data elegantly

Filter function in Vue3: Handling data elegantly

Vue is a popular JavaScript framework with a large community and a powerful plug-in system. In Vue, the filter function is a very practical tool that allows us to process and format data in templates. There have been some changes to the filter functions in Vue3. In this article, we will take a deep dive into the filter functions in Vue3 and learn how to use them to handle data gracefully.

What is a filter function?

In Vue, the filter function is a function used to process and format data. The use of the filter function is very simple. You only need to use the pipe symbol | in the template to connect the data and the filter function. For example, we can use the built-in filter function capitalize provided by Vue to capitalize the first letter of the string:

{{ message | capitalize }}

where message is the data we want to process, capitalize is the built-in filter function provided by Vue.

Changes in Vue3

In Vue3, there have been some changes in the way filter functions are implemented. Vue3 no longer provides built-in filter functions, but implements filter functions through custom functions. This means we need to write the filter function ourselves, but it also brings more flexibility and scalability.

Implementing the filter function

To implement the filter function, we need to define a global filter function in the root instance of the Vue application. Here is a simple example showing how to write a filter function that converts a string to uppercase:

const app = Vue.createApp({
  data() {
    return {
      message: 'hello world'
    }
  },
  filters: {
    uppercase(value) {
      return value.toUpperCase()
    }
  }
})

In this example, we create a global filter using the filters option Converter function uppercase, which accepts a value (value) as a parameter, converts it into uppercase letters and returns it.

Using the filter function

Using the filter function in the template is very simple, just use the pipe character in the data binding expression|The data and filter functions are connected. The following is an example of converting a string to uppercase and intercepting the first 5 characters:

<p>{{ message | uppercase | slice(0, 5) }}</p>

In this example, we first use the filter function uppercase to message## The value of # is converted to uppercase letters, and then the first 5 characters are intercepted using the slice filter function, and the result is displayed in the

tag. It should be noted that in Vue3, we can add multiple filter functions after the pipe character, and they will be applied to the data in order.

Conclusion

The filter function in Vue3 is a very practical tool. They separate the processing and formatting of data from the rendering of templates, enhancing the readability of Vue applications. performance and maintainability. In Vue3, the implementation of the filter function has changed. We need to write the filter function ourselves, but it also brings more flexibility and scalability. I hope this article can help everyone better understand the filter function in Vue3 and apply it in actual development.

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