\b and \B let you inspect whether a string is at the beginning or at the end of a word:

• \b matches a set of characters at the beginning or end of a word
• \B matches a set of characters not at the beginning or end of a word

Example:

'I saw a bear'.match(/\bbear/)    //Array ["bear"]
'I saw a beard'.match(/\bbear/)   //Array ["bear"]
'I saw a beard'.match(/\bbear\b/) //null
'cool_bear'.match(/\bbear\b/)     //null

Lessons in this unit: