Detailed explanation of data binding functions in Vue documentation

Vue is an open source JavaScript framework, which is mainly used to build user interfaces. The core of Vue is data binding, which provides a convenient and efficient way to achieve two-way binding between data and views.

Vue’s data binding mechanism is handled through some special functions. These functions can help us automatically bind the data in the template to the corresponding properties in the JavaScript object, so that when the properties in the JavaScript object are modified, the data in the template will be automatically updated. This article will introduce the data binding functions in the Vue document in detail.

1. {{ }} and v-bind

In Vue, we can use {{ }} and v-bind directives to implement data binding.

{{ }} is a simple text interpolation syntax that renders data into the DOM. Just use double brackets in the template to wrap the data. For example:

<div>{{ message }}</div>

The message here is a property in a JavaScript object.

The v-bind directive can bind an object property to a specific characteristic of an element. For example:

<img  src="/static/imghwm/default1.png"  data-src="imageSrc"  class="lazy"  v-bind: alt="Detailed explanation of data binding functions in Vue documentation" >

The imageSrc here is a property in a JavaScript object.

2. Computed property

A calculated property is a function that can calculate a new property value based on other properties. Its value is cached and only recalculated when its dependent properties change.

Using calculated attributes in templates can eliminate tedious logical operations and directly display the results. For example:

<p>{{ fullName }}</p>

The calculated property is defined as follows:

computed: {
  fullName: function () {
    return this.firstName + ' ' + this.lastName
  }
}

3. Method

The method is the most commonly used data binding method in Vue. When we need to execute JavaScript code after an event is triggered in the template, we can use methods.

When calling a method in a template, you can use the v-on directive to bind the method to a specific event. For example:

<button v-on:click="doSomething">Click me</button>

The method is defined as follows:

methods: {
  doSomething: function () {
    // code here
  }
}

4. Listener

A listener is a method that can observe changes in object properties and perform response operations function. When the property is modified, Vue will call the listener function, and we can execute arbitrary Javascript code in the listener function.

The listener is defined as follows:

watch: {
  message: function (newValue, oldValue) {
    // code here
  }
}

The message here is the attribute in the JavaScript object that needs to be observed, and newValue and oldValue respectively represent the value after the attribute changes and the value before the change.

Summary: Vue’s data binding mechanism provides us with a convenient way to handle the relationship between data and views. More importantly, it makes our code look more concise and understandable. . When using Vue, we should understand the usage rules of data binding functions in detail to avoid unnecessary errors.

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