改变this 指向的3种方法-优快云博客

本文介绍了在JavaScript中解决this指向问题的三种方法：1. 在函数内部声明变量that并将其赋值为this；2. 使用bind方法绑定外部的this；3. 直接使用箭头函数。通过具体实例展示了每种方法的应用。

1.在函数内部声明一个that，然后将this赋值给that,

var that=this;

最后用that 代替this使用

<!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>Document</title>
</head>
<body>
    
</body>
<script>
    const team={
        members:["Herry","hrll"],
        teamName:"Es6",
        teamSummary:function() {
            var that=this;
            return this.members.map(function(member) {
                return `${member}隶属于${that.teamName}`
            })
        }
    }
    console.log(team.teamSummary())
</script>
</html>

2.用bind方法，绑定外部的this

<!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>Document</title>
</head>
<body>
    
</body>
<script>
    const team={
        members:["Herry","hrll"],
        teamName:"Es6",
        teamSummary:function() {
            
            return this.members.map(function(member) {
                return `${member}隶属于${this.teamName}`
            }.bind(this))
        }
    }
    console.log(team.teamSummary())
</script>
</html>

3.直接使用箭头函数

<!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>Document</title>
</head>
<body>
    
</body>
<script>
    const team={
        members:["Herry","hrll"],
        teamName:"Es6",
        teamSummary:function() {
            
            return this.members.map((member)=> {
                return `${member}隶属于${this.teamName}`
            })
        }
    }
    console.log(team.teamSummary())
</script>
</html>