es6的扩展运算符（...）的用途

1.合并数组

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var arr1 = ['two', 'three'];

var arr2 = ['one', ...arr1, 'four', 'five'];

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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}

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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}

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解构与展开详解