ES6课程---5、形参默认值

一、总结

一句话总结：

形参默认值就是给函数的形参指定默认的参数，如果传参数进来了，就用传进来的参数，如果没有传递参数进来，就用默认值，比如 function Point(x=0,y=0) {}

function Point(x=0,y=0) {
  this.x=x;
  this.y=y;
}
let point=new Point(12,23);
console.log(point);
let point1=new Point();
console.log(point1);

二、形参默认值

博客对应课程的视频位置：5、形参默认值
https://www.fanrenyi.com/video/24/200

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>形参默认值</title>
 6 </head>
 7 <body>
 8 <!--
 9 
10 -->
11 <script>
12     //定义一个点的坐标的构造函数
13     function Point(x=0,y=0) {
14         this.x=x;
15         this.y=y;
16     }
17     let point=new Point(12,23);
18     console.log(point);
19     let point1=new Point();
20     console.log(point1);
21 
22 </script>
23 </body>
24 </html>