18个JavaScript编写简洁高效代码的技巧分享

function add(a, b) {
  return a + b;
}

// Arrow function
const add = (a, b) => a + b;

const str = "Hello!";
const arr = Array.from(str);

console.log(arr); //Output: ['H', 'e', 'l', 'l', 'o', '!']

const person = {
    name: 'John', 
    age: 25,
    profession: 'Programmer'
}
console.table(person);

const PI = 3.14;
let timer = 0;

const person = {
    name: 'John', 
    age: 25,
    profession: 'Programmer'
}

//Instead of this 👇
console.log(person.name);
console.log(person.age);

//Use this👇
const {name, age} = person;
console.log(name);
console.log(age);

function greet(name) {
  name = name || 'Person';
  console.log(`Hello, ${name}!`);
}

greet(); //Output: Hello, Person!
greet("John"); //Output: Hello, John!

let numbers = [1, 2, 3, 4];
numbers.length = 0;
console.log(numbers); //Output: []

const jsonStr = '{"name": "John", "age": 25}';
const person = JSON.parse(jsonStr);
console.log(person); 
//Output: {name: 'John', age: 25}

const numbers = [1, 2, 3, 4];
const doubled = numbers.map(num => num * 2);
console.log(numbers); //Output: [1, 2, 3, 4]
console.log(doubled); //Output: [2, 4, 6, 8]

const person = {
    name: 'John', 
    age: 25
};
Object.seal(person);
person.profession = "Programmer";
console.log(person); //Output: {name: 'John', age: 25}

const person = {
    name: 'John', 
    age: 25
};
Object.freeze(person);
person.name = "Mark";
console.log(person); //Output: {name: 'John', age: 25}

const arrWithDuplicates = [1, 12, 2, 13, 4, 4, 13];
const arrWithoutDuplicates = [...new Set(arrWithDuplicates)];
console.log(arrWithoutDuplicates); 
//Output: [1, 12, 2, 13, 4]

let x = 7, y = 13;
[x, y] = [y, x];
console.log(x); //13

const arr1 = [1, 2, 3];
const arr2 = [9, 8, 7];

const arr3 = [...arr2];
const mergedArr = [...arr1, ...arr2];

console.log(arr3); //[9, 8, 7]
console.log(mergedArr); //[1, 2, 3, 9, 8, 7]

const name = 'John';
const message = `Hello, ${name}!`;

const age = 20;

//Instead of this👇
if(age>=18){
    console.log("You can drive");
}else{
    console.log("You cannot drive");
}

//Use this👇
age >= 18 ? console.log("You can drive") : console.log("You cannot drive");

const num1 = 5;
const num2 = '5';

//Instead of using ==
if (num1 == num2) {
  console.log('True');
} else {
  console.log('False');
}

//Use ===
if (num1 === num2) {
  console.log('True');
} else {
  console.log('False');
}

// Don't declare variable like this
const a = 18;

// use descriptive names
const numberOfTips = 18;