Awesome JavaScript Snippets (one-liners) Generate a random number between two values const randomNumber = ( min , max ) => Math . floor ( Math . random ( ) * ( max - min + 1 ) ) + min ; Check if a number is an integer const isInteger = ( num ) => Number . isInteger ( num ) ; Check if a value is null or undefined const isNil = ( value ) => value == null ; Check if a value is a truthy value const isTruthy = ( value ) => Boolean ( value ) ; Check if a value is a falsy value const isFalsy = ( value ) => ! value ; Check if a value is a valid credit card number const isCreditCard = ( cc ) => {
const regex = / (?: (?< visa > 4 [ 0 - 9 ] { 12 } (?: [ 0 - 9 ] { 3 } ) ? ) | (?< mastercard > 2 5 [ 1 - 7 ] [ 0 - 9 ] { 14 } ) | (?< discover > 6 (?: 0 1 1 | 5 [ 0 - 9 ] { 2 } ) (?: [ 0 - 9 ] { 12 } ) ) (?< amex > 3 [ 4 7 ] [ 0 - 9 ] { 13 } ) | (? ( 8 ) ^ (?: 2 1 3 1 | 1 8 0 0 | 3 5 \d { 3 } ) \d { 11 } $ ) ) / ;
return regex . test ( cc ) ;
} Check if a value is an object const isObject = ( value ) => value !== null && typeof value === 'object' ; Check if a value is a function const isFunction = ( value ) => typeof value === 'function' ; Remove Duplicates from Array const removeDuplicates = ( array ) => [ ...new Set ( array ) ] ; Check if a value is a promise const isPromise = ( promise ) => Promise . resolve ( promise ) === promise ; Check if a value is a valid email address const isEmail = ( email ) => {
const regex = / ( ( [ ^ < > ( ) \[ \] \\ . , ; : \s @ " ] + ( \. [ ^ < > ( ) \[ \] \\ . , ; : \s @ " ] + ) * ) | ( " .+ " ) ) @ ( ( \[ [ 0 - 9 ] { 1 , 3 } \. [ 0 - 9 ] { 1 , 3 } \. [ 0 - 9 ] { 1 , 3 } \. [ 0 - 9 ] { 1 , 3 } ] ) | ( ( [ a - z A - Z \- 0 - 9 ] + \. ) + [ a - z A - Z ] { 2 , } ) ) / ;
return regex . test ( email ) ;
} Check if a string ends with a given suffix const endsWith = ( str , suffix ) => str . endsWith ( suffix ) ; Check if a string starts with a given prefix const startsWith = ( str , prefix ) => str . startsWith ( prefix ) ; Check if a value is a valid URL const isURL = ( url ) => {
const regex = / (?: h t t p ( s ) ? : \/ \/ ) ? [ \w . - ] + (?: \. [ \w \. - ] + ) + [ \w \- \. _ ~ : / ? # [ \] @ ! \$ & ' \( \) \* \+ , ; = . ] + / ;
return regex . test ( url ) ;
} Check if a value is a valid hexadecimal color code const isHexColor = ( hex ) => {
const regex = / ^ # ( [ A - F a - f 0 - 9 ] { 6 } | [ A - F a - f 0 - 9 ] { 3 } ) $ / ;
return regex . test ( hex ) ;
} Check if a value is a valid postal code const isPostalCode = ( postalCode , countryCode ) => {
const regexMap = {
US : / ^ ( [ 0 - 9 ] { 5 } ) (?: [ - \s ] * ( [ 0 - 9 ] { 4 } ) ) ? $ / ,
CA : / ^ ( [ A - Z a - z ] \d [ A - Z a - z ] [ - ] ? \d [ A - Z a - z ] \d ) $ / } ;
const regex = regexMap [ countryCode . toUpperCase ( ) ] ;
return regex ? regex . test ( postalCode ) : false ;
} Check if a value is a DOM element const isDOMElement = ( value ) => value instanceof Element ; Check if a value is a valid CSS length (e.g. 10px, 1em, 50%) const isCSSLength = ( value ) => {
const regex = / ^ [ - + ] ? ( \d * \. ) ? \d + ( e m | e x | p x | i n | c m | m m | p t | p c | % | v w | v h | v m i n | v m a x ) $ / ;
return regex . test ( value ) ;
} Check if a value is a valid date string (e.g. 2022-09-01,yyyy/mm/dd, etc.) const isDateString = ( value ) => ! isNaN ( Date . parse ( value ) ) ; Calculate the factorial of a number const factorial = ( num ) => {
if ( num < 0 ) return - 1 ; else if ( num === 0 ) return 1 ; else return ( num * factorial ( num - 1 ) ) ; } Find the maximum value in an array const max = ( array ) => Math . max ( ...array ) ; Find the minimum value in an array const min = ( array ) => Math . min ( ...array ) ; Calculate the sum of values in an array const sum = ( array ) => array . reduce ( ( acc , val ) => acc + val , 0 ) ; Create an array of unique values from an array of objects based on a specific key const uniqueBy = ( array , key ) => [ ...new Map ( array . map ( ( obj ) => [ obj [ key ] , obj ] ) ) . values ( ) ] ; Quickly create an array of characters from a string const string = "abcdefg" ;
const array = [ ...string ] ; Quickly create an object with all the properties and values of another object, but with a different key for each property const original = { a : 1 , b : 2 , c : 3 } ;
const mapped = { ...original , ...Object . keys ( original ) . reduce ( ( obj , key ) => ( { ...obj , [ key . toUpperCase ( ) ] : original [ key ] } ) , { } ) } ; Quickly create an array of numbers from 1 to 10 const array = [ ...Array ( 10 ) . keys ( ) ] . map ( i => i + 1 ) ; const shuffle = ( array ) => array . sort ( ( ) => Math . random ( ) - 0.5 ) ; Convert an array-like object (such as a NodeList) to an array const toArray = ( arrayLike ) => Array . prototype . slice . call ( arrayLike ) ; //Ascending
const sortAscending = ( array ) => array . sort ( ( a , b ) => a - b ) ;
//Descending
const sortDescending = ( array ) => array . sort ( ( a , b ) => b - a ) ; const debounce = ( fn , time ) => {
let timeout ;
return function ( ...args ) {
clearTimeout ( timeout ) ;
timeout = setTimeout ( ( ) => fn . apply ( this , args ) , time ) ;
} ;
} ; Open a new tab with a given URL const openTab = ( url ) => {
window . open ( url , "_blank" ) ;
} ; Get the difference between two dates const dateDiff = ( date1 , date2 ) => Math . abs ( new Date ( date1 ) - new Date ( date2 ) ) ; Generate a random string of a given length const randomString = ( length ) => {
let result = "" ;
const characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" ;
for ( let i = 0 ; i < length ; i ++ ) {
result += characters . charAt ( Math . floor ( Math . random ( ) * characters . length ) ) ;
}
return result ;
} ;
