You can embed the type information in special JS comments that the checker understands: http://flowtype.org/blog/2015/02/20/Flow-Comments.html http://flowtype.o

You can embed the type information in special JS comments that the checker understands: http://flowtype.org/blog/2015/02/20/Flow-Comments.html http://flowtype.org/blog/2015/02/20/Flow-Comments.html Your existing minification step will remove the comments. But even if you don't remove the comments the code will still run.