You're probably using match, and nobody told you the names would be capitalized or not.

Having the exact same problem, don't understand what's going on....

Hello! Can somebody tell me please why the method join is not working in this task? Test all passed, only method join is not
Test Passed: Value == 'S.H'
Test Passed: Value == 'P.F'
Test Passed: Value == 'E.C'
Test Passed: Value == 'P.F'
Test Passed: Value == 'D.M'
TypeError: Cannot read property 'join' of null
at abbrevName
at /home/codewarrior/index.js:20:19
at /home/codewarrior/index.js:52:5
at Object.handleError