<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>生命周期</title> <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script> </head> <body> <div id=‘app‘></div> <script> let app = new Vue({ el: ‘#app‘, data: { a: 1 }, created: function () { // `this` 指向 vm 实例 console.log(‘a is: ‘ + this.a) } }) /* 不要在选项属性或回调上使用箭头函数，比如 created: () => console.log(this.a) 或 vm.$watch(‘a‘, newValue => this.myMethod())。 因为箭头函数并没有 this，this 会作为变量一直向上级词法作用域查找，直至找到为止， 经常导致 Uncaught TypeError: Cannot read property of undefined 或 Uncaught TypeError: this.myMethod is not a function 之类的错误 */ </script> </body> </html>
原文：https://www.cnblogs.com/chosen-chen/p/11246263.html