实例演示对象与数组的解构赋值 2. 实例演示访问器属性,并描述与普通属性之间的区别与联系

对象与数组的解构赋值

console.log("-------1.数组-------");
let [uname, salary] = ["libai", "15000"];
console.log(uname, salary);
[uname, salary] = ["luxun", "15500"];
console.log(uname, salary);
console.log("-------1.值数量 < 变量数量，默认值-------");
[uname, salary, gender = "man"] = ["sushi", "33000"];
console.log(uname, salary, gender);
console.log("-------2.值数量 > 变量数量，...rest------");
[uname, ...arr] = ["zhuxun", "36000", "man"];
console.log(uname, arr);
console.log(uname, ...arr);
console.log("-------应用场景：交换二个数-------");
let x = 10;
let y = 5;
console.log(`x = ${x}, y = ${y}`);
[y, x] = [x, y];
console.log(`x = ${x}, y = ${y}`);
console.log("-------2.对象-------");
// ? 变量名 === 属性名
let { num, price } = { num: 1, price: 5000 };
console.log(num, price);
// {}不能出现在等号左边(左值),所以加上括号()转成表达式
({ num, price } = { num: 2, price: 6000 });
console.log(num, price);
// 命名冲突: 别名
({ num, price: uprice } = { num: 3, price: 7000 });
console.log(num, uprice);
console.log("--------// 应用场景1: 克隆对象---------");
let study = { name: "libai", score: 60 };
console.log(study);
// 如果想创建二个不相关的对象,值又完全一样,只能克隆
let { ...obj } = study;
console.log(obj);
console.log(obj === study);
console.log("--------// 应用场景2 : 解构传参---------");
let show = function (user) {
  return `${user.num}: ( ${user.price} )`;
};
let user = { num: 3, price: 6000 };
console.log(show(user));
// * 使用对象解构进行简化传参
show = function ({ num, price }) {
  return `${num}: ( ${price} )`;
};
user = { num: "5", price: "7000" };
console.log(show(user));

访问器属性,并描述与普通属性之间的区别与联系

let course = {
  lesson: {
    name: "math",
    score: 60,
  },
  getScore() {
    return {
      name: this.lesson.name,
      course: this.lesson.score,
    };
  },
  setScore(score) {
    if (score >= 0 && score <= 100) {
      this.lesson.score = score;
    } else {
      console.log("成绩必须在0-100分之间");
    }
  },
};
console.log(course.lesson.score);
console.log(course.getScore());
course.setScore(70);
console.log(course.getScore());
console.log('-------使用"访问器属性" 就可以实现-------');
course = {
  lesson: {
    name: "chinese",
    score: 80,
  },
  score: 85,
  // getScore ===> get score
  // 普通方法 ===> 访问器属性
  // 如果使用访问器属性, get必须要有, set 可选
  get score() {
    return {
      name: this.lesson.name,
      course: this.lesson.score,
    };
  },
  set score(score) {
    if (score >= 0 && score <= 100) {
      this.lesson.score = score;
    } else {
      console.log("成绩必须在0-100分之间");
    }
  },
};
console.log(course.score);
course.score = 50;
console.log(course.score);