Pattern or library for recursive descent parsing a stream asynchronously in node.js

In a synchronous runtime (say c# ) I can write a very simple recursive descent parser for a file that can output results as it reads the file. So I never need to buffer the file. There can be a complicated state machine pulling from the input, and it's nice and simple.

Something like this

BinaryStream s = File.Open("somefile");

while(s.CanRead() ){
     var type = s.readInt32();

     if ( type == 1 ) {
         emit(readSomeBinaryStructure(s);
     }else if ( type == 2 ){
         emit ( readSomeOtherBInaryStructure(s)) 
         emit (s.readString() );
       }else{
         emit(type);
     } 
}

In Node I have something very complicated because I get chunks of data which I can't determine the alignment on a structure.

What patterns are there to deal with this - something simple seems to get very complicated. The file I am parsing is many gigabytes so there is not enough ram to load it into ram first.

stream.on("data", f=>{
      //somehow deal with a async recursive descent parser - saving the state between each chunk of data

}

Thanks for any thoughts.