title: "TypeError: Cannot read property 'indexOf' of undefined" raised when using packages "onoff" or "rpi-gpio" with WebPack
body: <p>I wrote a Node.JS project for the Raspberry PI, to control the GPIO.<br>
  This is my first time using GPIO.</p>
  
  <p>The project uses the "onoff" package to communicate with GPIO. And the compiler is WebPack.<br>
  I can compile the project without issue.<br>
  But when I run the application on the RaspberryPI, I receive this error:</p>
  
  <pre><code>webpack:///./node_modules/bindings/bindings.js?:178
    if (fileName.indexOf(fileSchema) === 0) {
                 ^
  
  TypeError: Cannot read property 'indexOf' of undefined
      at Function.getFileName (webpack:///./node_modules/bindings/bindings.js?:178:16)
      at bindings (webpack:///./node_modules/bindings/bindings.js?:82:48)
      at eval (webpack:///./node_modules/epoll/epoll.js?:7:86)
      at eval (webpack:///./node_modules/epoll/epoll.js?:15:3)
      at Object../node_modules/epoll/epoll.js (/home/pi/xilium/raspi.node/Raspi.node/dist/raspi.multi-monitor.js:809:1)
      at __webpack_require__ (/home/pi/xilium/raspi.node/Raspi.node/dist/raspi.multi-monitor.js:20:30)
      at eval (webpack:///./node_modules/rpi-gpio/rpi-gpio.js?:6:20)
      at Object../node_modules/rpi-gpio/rpi-gpio.js (/home/pi/xilium/raspi.node/Raspi.node/dist/raspi.multi-monitor.js:1375:1)
      at __webpack_require__ (/home/pi/xilium/raspi.node/Raspi.node/dist/raspi.multi-monitor.js:20:30)
      at eval (webpack:///./src/raspi.multi-monitor.ts?:29:15)
  </code></pre>
  
  <p>So, I tried replacing the "onoff" package with "rpi-gpio". Unfortunately, the result is the same.</p>
  
  <p>It seems that there is a configuration issue for "epoll" package (a dependence of "onoff" and "rpi-gpio").  </p>
  
  <p>Can anyone help me?</p>