展开语法

作者: 小雪洁 | 来源:发表于2020-03-17 17:36 被阅读0次

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>展开语法</title>
    </head>
    <body>
        <script>
            //合并数组
            let hxj =["hao","xue","jie"];
            let ydc=["yang","ding","chuan"];
            console.log(hxj);// ["hao", "xue", "jie"]
            console.log(...hxj);//hao xue jie
            //使用for-in循环ydc追加到hxj
            /* for(let key in ydc){
                hxj.push(ydc[key]);
            }
             console.log(hxj);//["hao", "xue", "jie", "yang", "ding", "chuan"]
            */
            //注意数组循环for-of 里的循环变量直接就是值
            /* for(const value of ydc){
                hxj.push(value);
            } 
            console.log(hxj);//["hao", "xue", "jie", "yang", "ding", "chuan"]
            */
            //使用展开语法合并数组
            let arr=[...hxj,...ydc];
            console.log(arr);
            //使用展开语法传递多个参数
            function sum(...args){
                return args.reduce((s,i)=>{
                    return (s += i);
                },0)
            }
            console.log(sum(1,2,3));//6
            
        </script>
    </body>
</html>