数组，对象，传参解构; 访问器属性的get,set

1. 数组，对象，传参解构

1)数组解构

• 左边是右边的模板
  let [a, b, c,] = [1, 2, 3]
  console.log(a, b, c)
• 用…代替很多
  [a, b, …c] = [1, 2, 3, 4, 5, 6];
  console.log(a, b, …c)
• 用,,,代替数值，如果只需要其中的一个
  [, , , a, ,] = [1, 2, 3, 4, 5, 6]
  console.log(a);
• 交换解析
  [a, b] = [b, a]

2) 对象解构
let item = { id: 10, name: “mobiltelephone” };

  let id = item.id;
  let name = item.name;
  console.log("id = %d, name = %s", id, name);

3)传参解构

• 数组传参
  let sum = ([a, b]) => a + b;
  console.log(sum([10, 20]));
• 对象传参
  let getUser = ({ name, email }) => [name, email];
  console.log(getUser({name: “Peter”, email: “admin@abc.com”}));

2. 访问器属性的get,set

• get: 访问器属性的读取操作
• set: 访问器属性的写的操作

const product = {
data.[
{id: 1, name: “computer”, price: 1000, num: 5 },
{id: 2, name: “camera”, price: 2000, num: 5 },
],
getAmounts(){
return this.data.reduce((t, c) => (t += c.price c.num), 0);
},
};
console.log(“sum = %d dollas”, product.getAmounts());
get total () {
return this.data.reduce((t, c) => (t += c.price c.num), 0);

• 访问器属性的的优先级高于同名的普通属性
  let user = {

      data: {name},
      get name() {
          return this.data.name;
      };
      set name(v) {
          this.data.name = v;
      },
  };
  user.name = "Peter";
  console.log(user.name);