// This function allows the user to register file extensions to custom
// Javascript 'compilers'. It accepts 2 arguments, where ext is a file
// extension as a string. E.g. '.coffee' for coffee-script files. compiler
-// is the second argument, which is a function that gets called then the
+// is the second argument, which is a function that gets called when the
// specified file extension is found. The compiler is passed a single
// argument, which is, the file contents, which need to be compiled.
//