1.合并数组
var arr1 = ['two', 'three'];
var arr2 = ['one', ...arr1, 'four', 'five'];
2.对象属性展开复制
const obj1 = {
a: 10,
b: 20
};
const obj2 = {
...obj1,
c: 30 };
console.log(obj2); // → {a: 10, b: 20, c: 30}
如果存在相同的值 后者覆盖前者
const obj2 = {
...obj1,
a: 30
};
console.log(obj2); // → {a: 30, b: 20}
