JavaScript中的简写语法分享

(() => {
  console.log("Hello, world!");
})();

const obj = {
  x: 1,
  add(y) {
    return this.x + y;
  },
  double: () => this.x * 2,
};
console.log(obj.add(2)); // 3
console.log(obj.double()); // NaN

class Person {
  constructor(name, age) {
    this.name = name;
    this.age = age;
  }

  sayHello() {
    console.log(
      `Hello, my name is ${this.name}, and I am ${this.age} years old.`
    );
  }
}
const alice = new Person("Alice", 20);
alice.sayHello(); // 'Hello, my name is Alice, and I am 20 years old.'

// math.js
export const add = (a, b) => a + b;
export const subtract = (a, b) => a - b;
export default {
  multiply: (a, b) => a * b,
  divide: (a, b) => a / b,
};

// main.js
import { add, subtract } from "./math.js";
import math from "./math.js";
console.log(add(1, 2)); // 3
console.log(subtract(3, 2)); // 1
console.log(math.multiply(2, 3)); // 6
console.log(math.divide(6, 2)); // 3

const obj = { x: 1, y: 2 };
const { x, y } = obj;
console.log(x, y); // 1, 2

const arr = [1, 2, 3];
const [a, b] = arr;
console.log(a, b); // 1, 2

const name = "Alice";
const age = 30;

// 传统写法
const user = {
  name: name,
  age: age,
};

// 简写写法
const user = { name, age };

const name = "Alice";
const age = 30;

// 传统写法
const message = "My name is " + name + " and I am " + age + " years old.";

// 简写写法
const message = `My name is ${name} and I am ${age} years old.`;

const obj = {
  foo() {
    // ...
  },
  bar() {
    // ...
  },
};

const double = (x) => x * 2;

const obj1 = {
  prop1: "value1",
  prop2: "value2",
  prop3: "value3",
};

const obj2 = {
  prop1: "value1",
  "prop with spaces": "value2",
  ["computedProp"]: "value3",
};

// 传统写法
if (done === true) {
  // ...
}

// 简写写法
if (done) {
  // ...
}