Getting piped input to node script

#!/usr/bin/env node

var getPipedInput = function() {
  return new Promise(function(resolve, reject) {

    var data = "";
    var self = process.stdin;
    var reading = false;
    self.on('readable', function() {
        var chunk = this.read();
        if (!reading) {
          if (chunk == null) {
            return resolve();
          } else {
            reading = true;
          }
        }

        if (chunk) {
          reading = true;
          data += chunk;
        }
    });

    self.on('end', function() {
      resolve(data);
    });

  });
};