insure export is capital

lib/bus.js

@@ -19,4 +19,6 @@ class Bus {
 
 } // end of Bus Class
 
-module.exports = Bus;
+module.exports = {
+  Bus
+};

lib/device.js

@@ -3,22 +3,22 @@
 // **********************************
 
 class Device {
-// bus is i2c-bus bus object
+  // bus is i2c-bus bus object
   constructor(bus, address, opts) {
     this.bus = bus.methods // artifact of adapting  ic2-bus to class format
     this.address = address
-            if (opts){
+    if (opts) {
       this.id = opts.id // must be unique within a bus
       this.desc = opts.desc
     }
 
   }
 
-        readRaw(length,buffer) {
+  readRaw(length, buffer) {
     return this.bus.i2cRead_p(this.address, length, buffer)
   }
 
-        writeRaw(length,buffer) {
+  writeRaw(length, buffer) {
     return this.bus.i2cWrite_p(this.address, length, buffer)
   }
 
@@ -30,7 +30,6 @@ class Device {
     return this.bus.writeByte_p(this.address, cmd, byte)
   }
 
-
   read2(cmd) {
     return this.bus.readWord_p(this.address, cmd)
   }
@@ -40,11 +39,11 @@ class Device {
   }
 
   // command with more than two bytes following
-        readBytes(){}
-        writeBytes(){}
+  readBytes() {}
+  writeBytes() {}
 
+}
 
-
-    }
-
-    module.exports = Device;
+module.exports = {
+  Device
+}