Master the responsiveness principle in Vue 3 and develop more efficient front-end applications

Vue is a popular front-end framework that simplifies the development process and improves user experience. Vue 3, as the latest version of Vue, has some changes and optimizations in the responsiveness principle, allowing developers to develop front-end applications more efficiently. This article will introduce the responsiveness principle of Vue 3 and share some development techniques to help readers better master Vue 3 and develop more efficient front-end applications.

The responsive principle of Vue 3 is implemented based on the Proxy and Reflect modules. Compared with Vue 2's Object.defineProperty method, Proxy provides a more powerful and flexible interception function, making Vue 3's responsive system more efficient and stable. Through Proxy, Vue 3 can track access and modification of objects to trigger corresponding updates.

In Vue 3, we can use the createApp function to create a Vue instance. Before creating a Vue instance, we need to define a responsive data object. Vue 3 provides reactive functions to achieve this. Using the reactive function, we can convert ordinary JavaScript objects into responsive data objects to monitor and update data. For example:

const data = { count: 0 }
const reactiveData = reactive(data)

In the above example, we convert an object named data into reactiveData, and reactiveData will automatically track the access and modification of the data object.

In addition to using the reactive function to convert objects, we can also use the ref function to convert an ordinary value into responsive data. The ref function returns a wrapper object that contains the value we passed in, and also provides a value attribute for obtaining and modifying the value. For example:

const count = ref(0)
console.log(count.value) // 输出0
count.value = 1
console.log(count.value) // 输出1

In Vue 3, we can use the toRefs function to convert the properties of the reactive object into reactive references. The advantage of this is that we can deconstruct the properties in the responsive object and use them, and these properties will remain responsive. For example:

const reactiveData = reactive({ count: 0 })
const { count } = toRefs(reactiveData)
console.log(count.value) // 输出0
count.value = 1
console.log(count.value) // 输出1

During the development process, we often need to calculate or filter data. Vue 3 provides the computed function to achieve this. The computed function receives a function as a parameter, which returns a computed property. Internal reactive dependencies automatically track changes in computed properties to enable automatic updates. For example:

const count = ref(0)
const doubleCount = computed(() => {
  return count.value * 2
})
console.log(doubleCount.value) // 输出0
count.value = 1
console.log(doubleCount.value) // 输出2

In addition to calculated properties, Vue 3 also provides the watch function to monitor changes in specific data. The watch function receives two parameters. The first parameter is the data to be monitored, and the second parameter is a callback function used to handle the logic of data changes. When the data specified by the first parameter changes, the callback function will be automatically called. For example:

const count = ref(0)
watch(count, (newVal, oldVal) => {
  console.log(newVal, oldVal)
})
count.value = 1 // 输出1, 0

In Vue 3, developers can develop front-end applications more efficiently by mastering the responsiveness principle and utilizing the related functions it provides. The reactive principle makes data monitoring and updating simple and reliable, while calculated properties and listening functions provide more flexibility and ways to organize data changes. I hope this article can help readers better understand and master the responsiveness principle of Vue 3, so as to develop more efficient front-end applications.

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