/hey/

matches hey wherever it was put inside the string.

If you want to match strings that start with hey, use the ^ operator:

/^hey/.test('hey')     //✅
/^hey/.test('bla hey') //❌

If you want to match strings that end with hey, use the $ operator:

/hey$/.test('hey')     //✅
/hey$/.test('bla hey') //✅
/hey$/.test('hey you') //❌

Combine those, and match strings that exactly match hey, and just that string:

/^hey$/.test('hey') //✅

To match a string that starts with a substring and ends with another, you can use .*, which matches any character repeated 0 or more times:

/^hey.*joe$/.test('hey joe')             //✅
/^hey.*joe$/.test('heyjoe')              //✅
/^hey.*joe$/.test('hey how are you joe') //✅
/^hey.*joe$/.test('hey joe!')            //❌

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