The difference between watch and methods in vue

In Vue, watch is used to respond to data changes and trigger callback functions; methods is used to execute user-defined methods, which can be called from any component method or template, and is mainly used to perform calculations, process data, or trigger operations. .

##The difference between watch and methods in vue

Main difference:

watch and methods are both Vue.js features used to respond to data changes, but they have different functions and uses :

watch :

Monitor changes in specific data.
• When the monitored data changes, the callback function is triggered.
• Mainly used to respond to data changes and perform corresponding operations.

methods:

Contains user-defined methods.
• Can be called from any component method or template.
• Mainly used to perform calculations, process data or trigger operations.

Detailed explanation:

Function:

• watch Used for Respond to data changes, and methods are used to perform operations.
• watch is declarative, while methods is imperative.

Grammar:

watch:

<code class="js">watch: {
  someProperty: {
    handler: function (val, oldVal) {
      // 数据变化时调用的函数
    },
    // 可选选项
    immediate: true,  // 立即触发
    deep: true,       // 深度监视
  },
}</code>

methods：

<code class="js">methods: {
  someMethod: function () {
    // 执行的操作
  },
}</code>

Usage:

• watch Usually used to respond to changes in component state or external data .
• methods For any operations or calculations that need to be performed in the component.

Best Practice:

Use
• watch to monitor data changes and take appropriate actions.
Use
• methods to perform operations and calculations that need to be called explicitly.
Avoid data manipulation in
• methods as it violates Vue.js's reactive system.

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