A practical JavaScript single-line function

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A journey of a thousand miles begins with single step

This article has put together some useful Single-line JavaScript functions that will help you get your work done faster and spend more time with your girlfriend. Without further ado, let’s begin!

Time and date

Check that the date is valid

const isDateValid = (. val) = > !Number.isNaN(new Date(... val).valueOf())console.log(isDateValid("December 17, 1995 03:24:00"))
// true
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Check if the date is a weekend

const isWeekend = (date) = > [0.6].indexOf(date.getDay()) ! = = -1
console.log(isWeekend(new Date(2021.5.21))) //false
console.log(isWeekend(new Date(2021.5.20))) //true
// The current date is Monday, 2021.6.21
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The day of the year in which the search date is located

const dayOfYear = (date) = > Math.floor((date - new Date(date.getFullYear(), 0.0)) / 1000 / 60 / 60 / 24)
// The specified date and month should be subtracted by one
console.log(dayOfYear(new Date(2021.8.29)))
console.log(dayOfYear(new Date("2021-9-29")))
console.log(dayOfYear(new Date()))
/ / 272
/ / 272
/ / 272
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Calculate the number of days between two dates

const dayDif = (date1, date2) = > Math.ceil(Math.abs(date1.getTime() - date2.getTime()) / 86400000)
console.log(dayDif(new Date("2021-10-1"), new Date("2021-9-30")))
/ / 1
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Time to deal with

const timeFromDate = date= > date.toTimeString().slice(0.8)
console.log(timeFromDate(new Date()))
console.log(timeFromDate(new Date(2021.0.10.17.30.0)))
/ / 14:23:36
/ / 17:30:00
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digital

Check whether the numbers are even or odd

const isEven = (num) = > num % 2= = =0
console.log(isEven(5))
// false
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The average of multiple numbers

const average = (. args) = > args.reduce((a, b) = > a + b) / args.length
console.log(average(1.2.3.4.5))
/ / 3
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Generate a random number between two numbers

const random = (min, max) = > Math.floor(Math.random() * (max - min + 1) + min)
console.log(random(1.50))
// could be anything from 1 - 50
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string

Flip string

const reverse = str= > str.split(' ').reverse().join(' ')
console.log(reverse('hello world'))
// dlrow olleh
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Uppercase character string

const capitalize = (str) = > str.charAt(0).toUpperCase() + str.slice(1)
console.log(capitalize('hello world'))
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Truncate the string at the end

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...
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Truncate the string from the middle

// The function takes a string as the first argument, then the size of the string we want as the second argument, and then how many characters are needed to start and end from the 3rd and 4th arguments
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.// The required string size
  13.// Start at the number of bits in the original string
  17.// Stop intercepting from the original string
))
// A long story ... eventually ends!
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Generate random string (unique ID)

const randomString = () = > Math.random().toString(36).slice(2)
console.log(randomString())
// could be anything
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An array of

Get a unique value in an array (array decrement)

const uniqueArr = arr= > ([...new Set(arr)])
console.log(uniqueArr([1.2.3.1.2.3.4.5]))
// [1, 2, 3, 4, 5]
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Check if the variable is an array

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
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Disrupted array

const shuffleArray = (arr) = > arr.sort(() = > 0.5 - Math.random())
console.log(shuffleArray([1.2.3.4]))
// [1, 3, 2, 4]
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Verifies whether the array is empty

const isNotEmpty = arr= > Array.isArray(arr) && arr.length > 0
console.log(isNotEmpty([1.2.3]))
// true
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Different ways to merge multiple arrays

// PS: We can also use the Settings object to copy anything from the final array.
/ / (1) the concat ()
/ / (2)...
const merge = (a, b) = > a.concat(b)
const merge = (a, b) = > [...a, ...b]
const merge = [...new Set(a.concat(b))]
const merge = [...new Set([...a, ...b])]
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Boolean value

Get Boolean values at random

const getRandomBoolean = () = > Math.random() >= 0.5 
console.log(getRandomBoolean())
// true/false
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Toggle Boolean

// bool is stored somewhere in the upperscope
const toggleBool = () = >(bool = ! bool)//or
const toggleBool = b= >! bconsole.log(toggleBool(true))
// false
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Variable exchange

Swap two variables (semicolon required)

let foo = 'foo';
let bar = 'bar';
[foo, bar] = [bar, foo]
console.log([foo, bar])
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A short circuit

Longhand

let str = 'str'
if(str ! = =null|| str ! = =undefined|| str ! = =' ') {
  let fullName = str
}
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Shorthand

const fullName = str ||  buddy 
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To obtain`JavaScript`The actual type of language

Method A

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
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Method B

var a = () = > {}
 function getType(params) {
   let type = typeof(params)
   if(type ! = ='object') {
     return type
   }
   return Object.prototype.toString.call(params).replace(/^\[object (\S+)\]$/.'$1')}console.log(getType(a))
// function
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color

Color RGB to hexadecimal

const rgbToHex = (r, g, b) = > "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1)
console.log(rgbToHex(255.255.255))
// #ffffff
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Generates random hexadecimal colors

const randomHex = () = > ` #The ${Math.floor(Math.random() * 0xffffff).toString(16).padEnd(6."0")}`
console.log(randomHex())
/ / # 680244
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Cookie

Gets the value of the browser Cookie

const cookie = name= > `; The ${document.cookie}`.split(`; ${name}= `).pop().split('; '). The shift () XXX for the keyconsole.log(cookie('XXX'))
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Clear all cookies

const clearCookies = document.cookie.split('; ').forEach(cookie= > document.cookie = cookie.replace(/ ^ + /.' ').replace(/ =. * /.` =; expires=The ${new Date(0).toUTCString()}; path=/`))
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Get query parameters from the URL

Method A

const getParameters = (URL) = > {
  URL = JSON.parse(
    '{"' +
      decodeURI(URL.split("?") [1])
        .replace(/"/g.'\ \ "')
        .replace(/&/g.'",")
        .replace(/=/g.'" : "') +
      '"}'
  )
  return JSON.stringify(URL)
}
getParameters(window.location)
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Method B

Object.fromEntries(new URLSearchParams(window.location.search))
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The mobile terminal

Check if the user is on an Apple device

const isAppleDevice = () = > /Mac|iPod|iPhone|iPad/.test(navigator.platform)
console.log(isAppleDevice)
// true/false
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Check whether the user’s device is in dark mode

const isDarkMode = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches
console.log(isDarkMode)
// true/false
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other

Scroll to the top of the page

const scrollToTop = () = > window.scrollTo(0.0)
scrollToTop()
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Copy text to clipboard

/ / you may need to add a check to see whether there is the navigator, clipboard. WriteText
const copyTextToClipboard = async (text) => {
  await navigator.clipboard.writeText(text)
}
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Gets the text selected by the user

const getSelectedText = () = > window.getSelection().toString();
getSelectedText()
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Check if the current TAB is in view/focus

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