Regex Quick Reference

.

\d

\D

\w

\W

\s

\S

[aeiou]

[^aeiou]

[a-z]

[A-Z0-9]

\.

\*

\(

\\

^

$

^ and $ with the m flag

\bcat\b

a*

a+

colou?r

\d{4}

\d{2,}

\d{2,4}

<.+?>

\d+?

(\d{3})-(\d{4})

(?<year>\d{4})-(?<month>\d{2})

(?:https?)://

cat|dog

(\w)\1  # doubled letter

\d+(?=px)

\d+(?!px)

(?<=\$)\d+

(?<!\$)\d+

/pattern/g

/pattern/i

/pattern/m

/pattern/s

/\p{L}+/u

/[\p{Emoji}]/v

^[^\s@]+@[^\s@]+\.[^\s@]+$

https?:\/\/[\w.-]+(?:\.[\w.-]+)+[\w\-._~:/?#[\]@!$&'()*+,;=]*

^\d{4}-(0[1-9]|1[0-2])-(0[1-9]|[12]\d|3[01])$

^([01]\d|2[0-3]):[0-5]\d$

^#(?:[0-9a-fA-F]{3}){1,2}$

^((25[0-5]|2[0-4]\d|1?\d?\d)\.){3}(25[0-5]|2[0-4]\d|1?\d?\d)$

^(?=.*[a-z])(?=.*[A-Z])(?=.*\d).{8,}$

^[a-z0-9]+(?:-[a-z0-9]+)*$

^\s+|\s+$

/^\d+$/.test(input)

const m = text.match(/(\d+)/); m?.[1]

for (const m of text.matchAll(/(\w+)@(\w+)/g)) { }

text.replace(/(\w+) (\w+)/, "$2 $1")

text.split(/\s*,\s*/)

new RegExp(`^${word}$`, "i")