展开运算符

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8" />
        <title>Document</title>
    </head>
    <body>
        <script type="text/javascript" >
            let arr1 = [1,3,5,7,9]
            let arr2 = [2,4,6,8,10]
            console.log(...arr1); //展开一个数组
            let arr3 = [...arr1,...arr2]//连接数组

            //在函数中使用
            function sum(...numbers){
                return numbers.reduce((preValue,currentValue)=>{
                    return preValue + currentValue
                })
            }
            console.log(sum(1,2,3,4));

            //构造字面量对象时使用展开语法
            let person = {name:'tom',age:18}
            let person2 = {...person}
            //console.log(...person); //报错,展开运算符不能展开对象
            person.name = 'jerry'
            console.log(person2);
            console.log(person);

            //合并
            let person3 = {...person,name:'jack',address:"地球"}
            console.log(person3);

        </script>
    </body>
</html>

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