Regarding this pointing problem in vue (detailed tutorial)

I have been learning to use vue axios recently and found a problem during use. I will share it with you in the following summary. This article mainly introduces you to the relevant information about this pointing problem when vue uses axios. The article introduces it through sample code. It is very detailed, friends in need can refer to it.

Preface

As we all know, axios is a plug-in for Vue to request data that appears after vue-resource. After vue was updated to 2.0, the author Youda announced that he would no longer update vue-resource, but recommended axios. For more detailed introduction, you can refer here: //www.jb51.net/article/109444.htm

This article mainly introduces the pointing problem of this when Vue uses axios. I won’t say much more below. Let’s take a look at the detailed introduction.

1. Solution

When using axios to make network requests in vue, you will encounter that this does not point to vue, but is undefined , which can be solved using the arrow function "=>". As follows:

methods: {
 loginAction(formName) {
 this.$axios.post('http://127.0.0.1/u/subLogin', {
  username: this.username,
  password: this.password
 })
  .then(function(response){
  console.log(this); //这里 this = undefined
  })
  .catch((error)=> {
  console.log(error); //箭头函数"=>"使this指向vue
  });

 });
 }
}

2. Reason

The arrow function "=>" in ES6 internal this is the lexical scope, determined by the context Determined (that is, determined by the outer caller vue).

3. Off topic

Use the "=>" function, you can say goodbye to the previous two ways of writing:

bind(this)To change the this pointer of the anonymous function

hack writing methodvar _this= this;:

loginAction(formName) {
 var _this= this;
 this.$axios.post("...")
 .then(function(response){
  console.log(_this); //这里 _this 指向vue
 })
 });
 }

The above is what I compiled For everyone, I hope it will be helpful to everyone in the future.

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