19个 JavaScript 单行代码技巧

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

const escape = (str) => str.replace(/[&<>"']/g, (m) => ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' }[m]))

const uppercasewords = (str) => str.replace(/^(.)|s+(.)/g, (c) => c.toUpperCase())

uppercaseWords('hello world'); // 'Hello World'

const uppercaseWords = (str) => str.replace(/^(.)|s+(.)/g, (c) => c.toUpperCase())

const toCamelCase = (str) => str.trim().replace(/[-_s]+(.)?/g, (_, c) => (c ? c.toUpperCase() : ''));

toCamelCase('background-color'); // backgroundColortoCamelCase('-webkit-scrollbar-thumb'); // WebkitScrollbarThumbtoCamelCase('_hello_world'); // HelloWorldtoCamelCase('hello_world'); // helloWorld

const removeDuplicates = (arr) => [...new Set(arr)]

console.log(removeDuplicates([1, 2, 2, 3, 3, 4, 4, 5, 5, 6])) // [1, 2, 3, 4, 5, 6]

const flat = (arr) =>    [].concat.Apply(        [],        arr.map((a) => (Array.isArray(a) ? flat(a) : a))    )

// Orconst flat = (arr) => arr.reduce((a, b) => (Array.isArray(b) ? [...a, ...flat(b)] : [...a, b]), [])

flat(['cat', ['lion', 'tiger']]) // ['cat', 'lion', 'tiger']

const removeFalsy = (arr) => arr.filter(Boolean)

removeFalsy([0, 'a string', '', NaN, true, 5, undefined, 'another string', false])// ['a string', true, 5, 'another string']

const isEven = num => num % 2 === 0

isEven(2) // trueisEven(1) // false

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

random(1, 50) // 25random(1, 50) // 34

const average = (...args) => args.reduce((a, b) => a + b) / args.length;

average(1, 2, 3, 4, 5);   // 3

const round = (n, d) => Number(Math.round(n + "e" + d) + "e-" + d)

round(1.005, 2) //1.01round(1.555, 2) //1.56

const diffDays = (date, otherDate) => Math.ceil(Math.abs(date - otherDate) / (1000 * 60 * 60 * 24));

diffDays(new Date("2021-11-3"), new Date("2022-2-1"))  // 90

const dayOfYear = (date) => Math.floor((date - new Date(date.getFullYear(), 0, 0)) / (1000 * 60 * 60 * 24))

dayOfYear(new Date()) // 74

const randomColor = () => `#${Math.random().toString(16).slice(2, 8).padEnd(6, '0')}`

randomColor() // #9dae4frandomColor() // #6ef10e

rgbToHex(255, 255, 255)  // '#ffffff'

const clearCookies = () => document.cookie.split(';').forEach((c) => (document.cookie = c.replace(/^ +/, '').replace(/=.*/, `=;expires=${new Date().toUTCString()};path=/`)))

const isDarkMode = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches

[foo, bar] = [bar, foo]

const pause = (millis) => new Promise(resolve => setTimeout(resolve, millis))

const fn = async () => {  awAIt pause(1000)

console.log('fatfish') // 1s later}fn()