学会这20+个JavaScript单行代码，让你像专业人士一样编写代码

const getRandomBoolean = () => Math.random() >= 0.5;

console.log(getRandomBoolean());

// a 50/50 chance of returning true or false

const isWeekend = (date) => [0, 6].indexOf(date.getDay()) !== -1;

console.log(isWeekend(new Date(2021, 4, 14)));

// false (Friday)

console.log(isWeekend(new Date(2021, 4, 15)));

// true (Saturday)

const isEven = (num) => num % 2 === 0;

console.log(isEven(5));

// false

console.log(isEven(4));

// true

const uniqueArr = (arr) => [...new Set(arr)];

console.log(uniqueArr([1, 2, 3, 1, 2, 3, 4, 5]));

// [1, 2, 3, 4, 5]

const isArray = (arr) => Array.isArray(arr);

console.log(isArray([1, 2, 3]));

// true

console.log(isArray({ name: 'Ovi' }));

// false

console.log(isArray('Hello World'));

// false

const random = (min, max) => Math.floor(Math.random() * (max - min + 1) + min);

console.log(random(1, 50));

// could be anything from 1 - 50

const randomString = () => Math.random().toString(36).slice(2);

console.log(randomString());

// could be anything!!!

const scrollToTop = () => window.scrollTo(0, 0);

scrollToTop();

// bool is stored somewhere in the upperscope

const toggleBool = () => (bool = !bool);

//or

const toggleBool = b => !b;

[foo, bar] = [bar, foo];

const daysDiff = (date, date2) => Math.ceil(Math.abs(date - date2) / 86400000);

console.log(daysDiff(new Date('2021-05-10'), new Date('2021-11-25')));

// 199

const copyTextToClipboard = async (text) => {

  await navigator.clipboard.writeText(text);

};

// Merge but don't remove the duplications

const merge = (a, b) => a.concat(b);

// Or

const merge = (a, b) => [...a, ...b];

// Merge and remove the duplications

const merge = [...new Set(a.concat(b))];

// Or

const merge = [...new Set([...a, ...b])];

const trueTypeOf = (obj) => {

  return Object.prototype.toString.call(obj).slice(8, -1).toLowerCase();

};

console.log(trueTypeOf(''));

// string

console.log(trueTypeOf(0));

// number

console.log(trueTypeOf());

// undefined

console.log(trueTypeOf(null));

// null

console.log(trueTypeOf({}));

// object

console.log(trueTypeOf([]));

// array

console.log(trueTypeOf(0));

// number

console.log(trueTypeOf(() => {}));

// function

const truncateString = (string, length) => {

  return string.length < length ? string : `${string.slice(0, length - 3)}...`;

};

console.log(

  truncateString('Hi, I should be truncated because I am too loooong!', 36),

);

// Hi, I should be truncated because...

const truncateStringMiddle = (string, length, start, end) => {

  return `${string.slice(0, start)}...${string.slice(string.length - end)}`;

};

console.log(

  truncateStringMiddle(

    'A long story goes here but then eventually ends!', // string

    25, // 需要的字符串大小

    13, // 从原始字符串第几位开始截取

    17, // 从原始字符串第几位停止截取

  ),

);

// A long story ... eventually ends!

const capitalize = (str) => str.charAt(0).toUpperCase() + str.slice(1);

console.log(capitalize('hello world'));

// Hello world

const isTabInView = () => !document.hidden;  // Not hidden

isTabInView();

// true/false

const isAppleDevice = () => /Mac|iPod|iPhone|iPad/.test(navigator.platform);

console.log(isAppleDevice);

// true/false

// Longhand

const age = 18;

let greetings;

if (age < 18) {

  greetings = 'You are not old enough';

} else {

  greetings = 'You are young!';

}

// Shorthand

const greetings = age < 18 ? 'You are not old enough' : 'You are young!';

// Longhand

if (name !== null || name !== undefined || name !== '') {

  let fullName = name;

}

// Shorthand

const fullName = name || 'buddy';