regex

Regular Expression Basics
.	Any character except newline
a	The character a
ab	The string ab
a|b	a or b
a*	0 or more a's
	Escapes a special character

Regular Expression Quantifiers
*	0 or more
+	1 or more
?	0 or 1
{2}	Exactly 2
{2, 5}	Between 2 and 5
{2,}	2 or more
Default is greedy. Append ? for reluctant.

Regular Expression Groups
(...)	Capturing group
(?:...)	Non-capturing group
Y	Match the Y'th captured group

Regular Expression Character Classes
[ab-d]	One character of: a, b, c, d
[^ab-d]	One character except: a, b, c, d
[]	Backspace character
d	One digit
D	One non-digit
s	One whitespace
S	One non-whitespace
w	One word character
W	One non-word character

Regular Expression Assertions
^	Start of string
$	End of string
	Word boundary
B	Non-word boundary
(?=...)	Positive lookahead
(?!...)	Negative lookahead

Regular Expression Flags
g	Global Match
i	Ignore case
m	^ and $ match start and end of line

Regular Expression Special Characters
	Newline
	Carriage return
	Tab
	Null character
YYY	Octal character YYY
xYY	Hexadecimal character YY
uYYYY	Hexadecimal character YYYY
cY	Control character Y

Regular Expression Replacement
$$	Inserts $
$&	Insert entire match
$`	Insert preceding string
$'	Insert following string
$Y	Insert Y'th captured group

https://www.debuggex.com/cheatsheet/regex/javascript