Anchors
^: start of the string or the start of a line in a multiline pattern$: end of the string or the end of a line in a multiline pattern\b: word boundary\B: not word boundary (opposite of\b)
[!NOTE]
Anchors are non-quantifiable (i.e. cannot be followed by a quantifier).
Character sequences
.: any character except line breaks\w: any word character\W: any non-word character (opposite of\w)\s: any whitespace character\S: any non-whitespace character (opposite of\s)\d: any digit character\D: any non-digit character (opposite of\d)[abc]: a single character in the given set (herea,borc)[^abc]: a single character not in the given set (opposite of[abc])[a-z]: a single character in the given range (here betweenaandzinclusive)[^a-z]: a single character not in the given range (opposite of[a-z])[a-zA-Z]: a single character in either of the given ranges
[!TIP]
Use
\to escape special characters (e.g.\,/,[,],(,),{,}etc.).
Quantifiers
a?: zero or one ofa(equal toa{0,1})a*: zero or more ofa(equal toa{0,})a+: one or more ofa(equal toa{1,})a{3}: exactly 3 ofaa{3,}: 3 or more ofaa{3,5}: between 3 and 5 ofa(inclusive)
[!NOTE]
ais any valid quantifiable expression.
Groups
(ab): match and capture everything enclosed (here exactlyab)(a|b): match and capture either one character (hereaorb)(?:ab): match everything enclosed, without capturing
Flags
g: Globalm: Multilinei: Case insensitiveu: Unicode
Note that this cheatsheet is meant only as a starting point and is by no means a complete guide to all the features and nuances of regular expressions. You can also read 6 JavaScript Regular Expression features you can use today for a deeper dive into some more advanced features.
