How to use

ReadStream

function

in

1/fs

function readSingleFile(path, callback) {
 if (!isString(path)) {
  return callback();
 }
 var stream = fs.createReadStream(convertSlash(path));
 var done, buf;
 var execCallback = function(err) {
  if (done) {
   return;
  }
  done = true;
  stream.close();
  callback(err ? null : buf);
 };
 stream.on('data', function(data) {
  if (done) {
   return;
  }
  buf = buf ? Buffer.concat([buf, data]) : data;
  if (buf.length > MAX_SIZE) {
   execCallback();
  }
 });
 stream.on('error', execCallback);
 stream.on('end', execCallback);
}

 stream.close();
 triggerChange(data, body);
};

})
.then(
 () => fileStream.close(), 
 err => {
  fileStream.close();
  throw err;