These characters are special:

• \
• /
• [ ]
• ( )
• { }
• ?
• +
• *
• |
• .
• ^
• $

They are special because they are control characters that have a meaning in the regular expression pattern, so if you want to use them inside the pattern as matching characters, you need to escape them, by prepending a backslash:

/^\\$/
/^\^$/ // /^\^$/.test('^') ✅
/^\$$/ // /^\$$/.test('$') ✅

Lessons in this unit:

0:	Introduction
1:	Introduction
2:	Anchoring
3:	Match Items in Ranges
4:	Matching a Range Item Multiple Times
5:	Negating a Pattern
6:	Meta Characters
7:	Regular Expressions Choices
8:	Quantifiers
9:	Optional Items
10:	Groups
11:	Capturing Groups
12:	Using match and exec Without Groups
13:	Noncapturing Groups
14:	Flags
15:	Inspecting a Regex
16:	▶︎ Escaping
17:	String Boundaries
18:	Replacing
19:	Greediness
20:	Lookaheads
21:	Lookbehinds
22:	Unicode
23:	Unicode Property Escapes
24:	Examples