Vue data cannot use arrow function problem analysis
This article mainly introduces the problem that arrow functions cannot be used in vue data. This article introduces it to you in great detail through source code analysis and has certain reference value. Friends who need it can refer to it
First of all, you need to To be clear, a() {} and b: () => {} are different
let obj = {
a() {},
// 相当于
a:function() {},
b: () => {}
}##1 VUE .js source code analysis
Note that only the core code is designed hereThis code is also the UMD implementation principle. This article is not the focus. Those who are interested can explore it by themselves.(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
typeof define === 'function' && define.amd ? define(factory) :
(global.Vue = factory());
}(this, (function (){
'use strict';
console.log(this) //*undefined*
})))
(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
typeof define === 'function' && define.amd ? define(factory) :
(global.Vue = factory());
}(this, (function (){
'use strict';
function getData(data,vm) {
return data.call(vm, vm)
}
function initData(params) {
data = vm._data = typeof data === 'function'
? getData(data, vm)
: data || {};
}
initData()
})))
var obj = {
a: () => {
'use strict';
console.log(this,'a')
},
b() {
console.log(this,'b')
},
c() {
// window
let e = () => {
console.log(this,'e')
}
return e
}
}
obj.a() // window
obj.b() // obj
obj.c()() // obj
(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
typeof define === 'function' && define.amd ? define(factory) :
(global.Vue = factory());
}(this, (function (){
'use strict';
let vm = {}
var data = () => {
console.log(this);//undefined
return {
a: 1
}
}
function getData(data,vm) {
return data.call(vm, vm)
}
function initData(params) {
data = vm._data = typeof data === 'function'
? getData(data, vm)
: data || {};
}
initData()
console.log(vm);
})))data() {}this points to the Vm instance, so he will update with the instance.
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