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展开运算符
13_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>