How to modify the value of an array in Vue

Vue is a popular JavaScript framework for building modern web applications. In Vue, working with arrays is a common task. When you want to modify the values ​​in an array, you have a variety of options, and Vue's responsive design allows these changes to be automatically reflected in your UI. This article will introduce how to modify the value of an array in Vue.

Array modification in Vue

Vue encapsulates the array in JavaScript and adds responsive functionality to it. This feature enables Vue to detect data changes and update content in the DOM accordingly. Vue automatically updates the view when you modify the array. Here's how to modify the value of an array in Vue:

Direct modification

You can modify an array by assigning new values ​​directly. Here's a simple example:

// 定义一个数组
let myArray = ["a", "b", "c"]

// 直接更改数组的值
myArray[0] = "d"

// Vue自动更新UI
console.log(myArray) // ["d", "b", "c"]

Assigning a new value directly can cause Vue to not know when a change has occurred. Therefore, you can change the value of the array by changing the built-in methods on the array instance, such as push(), pop(), and splice().

Change the array in the Vue instance

When you change the array in the Vue instance, Vue will automatically update the content in the DOM. You can change an array by assigning it to a data property in your Vue instance. Here is an example:

new Vue({
  data: {
    myArray: ["a", "b", "c"]
  }
})

// 修改Vue实例中的数据
this.myArray[0] = "d"

// Vue自动更新UI
console.log(this.myArray) // ["d", "b", "c"]

Changing array methods in Vue instances

Vue instances have methods to change arrays. These methods automatically update the data in the Vue instance and change the content in the DOM. Here is an example using a Vue instance:

new Vue({
  data: {
    myArray: ["a", "b", "c"]
  },
  methods: {
    changeArray() {
      this.$set(this.myArray, 0, "d")
    }
  }
})

// 调用方法来更改数组
this.changeArray()

// Vue自动更新UI
console.log(this.myArray) // ["d", "b", "c"]

Vue array methods include push(), splice(), pop() and other methods that can change the array. When using these methods, Vue will automatically update the responsive data and update the UI.

Use Vue.set() to modify the array

Use Vue.set() to modify the array in the Vue instance. Vue.set() enables you to set new values ​​in an array and ensure that changes are tracked and responded to correctly. Here is an example using Vue.set():

new Vue({
  data: {
    myArray: ["a", "b", "c"]
  },
  methods: {
    changeArray() {
      this.$set(this.myArray, 0, "d")
    }
  }
})

// 使用Vue.set()修改数组
Vue.set(this.myArray, 0, "d")

// Vue自动更新UI
console.log(this.myArray) // ["d", "b", "c"]

Vue.set() takes three parameters: the array to modify, the index to modify, and the new value.

Summary

This article introduces different ways to modify the value of an array in Vue. You can modify an array by directly modifying the array, changing the array in the Vue instance, using the Vue instance's methods, and using Vue.set(). No matter which method you use, Vue will automatically update the UI.

Vue’s responsive design makes working with arrays easier and more efficient. When using Vue, you no longer have to manually update content in the DOM. Using the techniques covered in this article, you can confidently build impressive web applications using Vue.

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