The use of Vue data listening method watch
This article mainly introduces the use of Vue data monitoring method watch. It is quite good. Now I will share it with you and give it as a reference. Let’s take a look together
The watch itself is easy to understand. The watch is responsible for associating the data in the view with a certain function
When the data in the Vue view changes, the associated The function will be executed
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>监听方法watch的使用</title>
<script src="https://cdn.bootcss.com/vue/2.5.16/vue.js"></script>
</head>
<body>
<p id="root"></p>
<script>
var vm = new Vue({
el: "#root",
data: { obj: {name: "zhaoolee", age: 12} , tel:6666666},
template: `<p><p>姓名: {{obj.name}}</p>
<p>电话: {{tel}}</p>
<input type="text" v-model="obj.name">
<input type="text" v-model="tel"></p>`,
watch: {
obj: {
handler(){
console.log("obj被改变");
},
// 页面加载之初先执行一次handle
immediate: true,
// 深度检查属性,即使对象内部的属性值改变, 也能检测到(比较消耗性能)
deep: true
},
"obj.name": {
handler(){
console.log("=>obj.name被改变");
}
},
tel:{
handler(){
console.log("tel被改变");
}
}
}
})
</script>
</body>
</html>corresponds to an object, the key is the observation expression, and the value is the corresponding callback. The value can also be a method name, or an object containing options. Call $watch() for each key upon instantiation;
//使用官方vue-cli脚手架书写
<template>
//观察数据为字符串或数组
<input v-model="example0"/>
<input v-model="example1"/>
/当单观察数据examples2为对象时，如果键值发生变化，为了监听到数据变化，需要添加deep:true参数
<input v-model="example2.inner0"/>
</template>
<script>
export default {
data(){
return {
example0:"",
example1:"",
example2:{
inner0:1,
innner1:2
}
}
},
watch:{
example0(curVal,oldVal){
console.log(curVal,oldVal);
},
example1:'a'，//值可以为methods的方法名
example2:{
//注意：当观察的数据为对象或数组时，curVal和oldVal是相等的，因为这两个形参指向的是同一个数据对象
handler(curVal,oldVal){
conosle.log(curVal,oldVal)
},
deep:true
}
},
methods:{
a(curVal,oldVal){
conosle.log(curVal,oldVal)
}
}
}
</script>##
The above is the detailed content of The use of Vue data listening method watch. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
How to use magnet links
Feb 18, 2024 am 10:02 AM
Magnet link is a link method for downloading resources, which is more convenient and efficient than traditional download methods. Magnet links allow you to download resources in a peer-to-peer manner without relying on an intermediary server. This article will introduce how to use magnet links and what to pay attention to. 1. What is a magnet link? A magnet link is a download method based on the P2P (Peer-to-Peer) protocol. Through magnet links, users can directly connect to the publisher of the resource to complete resource sharing and downloading. Compared with traditional downloading methods, magnetic
Users encounter rare glitches: Samsung Watch smartwatches suddenly experience white screen issues
Apr 03, 2024 am 08:13 AM
You may have encountered the problem of green lines appearing on the screen of your smartphone. Even if you have never seen it, you must have seen related pictures on the Internet. So, have you ever encountered a situation where the smart watch screen turns white? On April 2, CNMO learned from foreign media that a Reddit user shared a picture on the social platform, showing the screen of the Samsung Watch series smart watches turning white. The user wrote: "I was charging when I left, and when I came back, it was like this. I tried to restart, but the screen was still like this during the restart process." Samsung Watch smart watch screen turned white. The Reddit user did not specify the smart watch. Specific model. However, judging from the picture, it should be Samsung Watch5. Previously, another Reddit user also reported
How to use mdf and mds files
Feb 19, 2024 pm 05:36 PM
How to use mdf files and mds files With the continuous advancement of computer technology, we can store and share data in a variety of ways. In the field of digital media, we often encounter some special file formats. In this article, we will discuss a common file format - mdf and mds files, and introduce how to use them. First, we need to understand the meaning of mdf files and mds files. mdf is the extension of the CD/DVD image file, and the mds file is the metadata file of the mdf file.
What software is crystaldiskmark? -How to use crystaldiskmark?
Mar 18, 2024 pm 02:58 PM
CrystalDiskMark is a small HDD benchmark tool for hard drives that quickly measures sequential and random read/write speeds. Next, let the editor introduce CrystalDiskMark to you and how to use crystaldiskmark~ 1. Introduction to CrystalDiskMark CrystalDiskMark is a widely used disk performance testing tool used to evaluate the read and write speed and performance of mechanical hard drives and solid-state drives (SSD). Random I/O performance. It is a free Windows application and provides a user-friendly interface and various test modes to evaluate different aspects of hard drive performance and is widely used in hardware reviews
How to download foobar2000? -How to use foobar2000
Mar 18, 2024 am 10:58 AM
foobar2000 is a software that can listen to music resources at any time. It brings you all kinds of music with lossless sound quality. The enhanced version of the music player allows you to get a more comprehensive and comfortable music experience. Its design concept is to play the advanced audio on the computer The device is transplanted to mobile phones to provide a more convenient and efficient music playback experience. The interface design is simple, clear and easy to use. It adopts a minimalist design style without too many decorations and cumbersome operations to get started quickly. It also supports a variety of skins and Theme, personalize settings according to your own preferences, and create an exclusive music player that supports the playback of multiple audio formats. It also supports the audio gain function to adjust the volume according to your own hearing conditions to avoid hearing damage caused by excessive volume. Next, let me help you
How to use Baidu Netdisk app
Mar 27, 2024 pm 06:46 PM
Cloud storage has become an indispensable part of our daily life and work nowadays. As one of the leading cloud storage services in China, Baidu Netdisk has won the favor of a large number of users with its powerful storage functions, efficient transmission speed and convenient operation experience. And whether you want to back up important files, share information, watch videos online, or listen to music, Baidu Cloud Disk can meet your needs. However, many users may not understand the specific use method of Baidu Netdisk app, so this tutorial will introduce in detail how to use Baidu Netdisk app. Users who are still confused can follow this article to learn more. ! How to use Baidu Cloud Network Disk: 1. Installation First, when downloading and installing Baidu Cloud software, please select the custom installation option.
How to use NetEase Mailbox Master
Mar 27, 2024 pm 05:32 PM
NetEase Mailbox, as an email address widely used by Chinese netizens, has always won the trust of users with its stable and efficient services. NetEase Mailbox Master is an email software specially created for mobile phone users. It greatly simplifies the process of sending and receiving emails and makes our email processing more convenient. So how to use NetEase Mailbox Master, and what specific functions it has. Below, the editor of this site will give you a detailed introduction, hoping to help you! First, you can search and download the NetEase Mailbox Master app in the mobile app store. Search for "NetEase Mailbox Master" in App Store or Baidu Mobile Assistant, and then follow the prompts to install it. After the download and installation is completed, we open the NetEase email account and log in. The login interface is as shown below
Simple guide to pip mirror source: easily master how to use it
Jan 16, 2024 am 10:18 AM
Get started easily: How to use pip mirror source With the popularity of Python around the world, pip has become a standard tool for Python package management. However, a common problem that many developers face when using pip to install packages is slowness. This is because by default, pip downloads packages from Python official sources or other external sources, and these sources may be located on overseas servers, resulting in slow download speeds. In order to improve download speed, we can use pip mirror source. What is a pip mirror source? To put it simply, just
