splitline.js

#!/usr/bin/env node

process.stdin.resume();
process.stdin.setEncoding('utf8');
 
function line_reader(stream, call_back) {
  var remainder = '';
  stream.on('data', function (chunk) {
      var lines = chunk.toString().split('\n');
      lines.unshift(remainder + lines.shift());
      remainder = lines.pop();
      lines.forEach(function(line) {
        call_back(line, false);
      }); 
    }); 
  stream.on('end', function() {call_back(remainder, true)});
};

/* ----------- example use ------------ */
line_reader(process.stdin, function(line, eof){
  process.stdout.write(line);
  if (!eof) process.stdout.write("\n");
});