"Danny is a terrific kid and we are all delighted he has committed his future to the club," said Alex boss Gudjon Thordarson.
"He is a talented lad and, just as importantly, he is also very hardworking, committed and focused. His attitude is spot on.
"Some young players think they have made it when they get a contract, but the truth is that is when the real hard work starts. I don't have any doubts about Danny in that respect because he gives everything he has got, whether that be in training or in matches.
"He scored a super first goal against Millwall and he put in a great cross for Tom Pope to score against Peterborough on Tuesday. He is an exciting talent."