more work for lazy bindings (noble#606)

* more work for lazy bindings

lib/noble.js

@@ -10,9 +10,9 @@ var Descriptor = require('./descriptor');
 
 function Noble(bindings) {
   this.initialized = false;
-  this.state = 'unknown';
-  this.address = 'unknown';
 
+  this.address = 'unknown';
+  this._state = 'unknown';
   this._bindings = bindings;
   this._peripherals = {};
   this._services = {};
@@ -48,20 +48,35 @@ function Noble(bindings) {
     }
   }.bind(this));
 
+  //lazy init bindings on first new listener, should be on stateChange
   this.on('newListener', function(event) {
     if (event === 'stateChange' && !this.initialized) {
       this._bindings.init();
       this.initialized = true;
     }
   }.bind(this));
+
+  //or lazy init bindings if someone attempts to get state first
+  Object.defineProperties(this, {
+    state: {
+      get: function () {
+        if (!this.initialized) {
+          this._bindings.init();
+          this.initialized = true;
+        }
+        return this._state;
+      }
+    }
+  });
+
 }
 
 util.inherits(Noble, events.EventEmitter);
 
 Noble.prototype.onStateChange = function(state) {
   debug('stateChange ' + state);
 
-  this.state = state;
+  this._state = state;
 
   this.emit('stateChange', state);
 };
@@ -73,25 +88,36 @@ Noble.prototype.onAddressChange = function(address) {
 };
 
 Noble.prototype.startScanning = function(serviceUuids, allowDuplicates, callback) {
-  if (this.state !== 'poweredOn') {
-    var error = new Error('Could not start scanning, state is ' + this.state + ' (not poweredOn)');
-
-    if (typeof callback === 'function') {
-      callback(error);
+  var scan = function(state) {
+    if (state !== 'poweredOn') {
+      var error = new Error('Could not start scanning, state is ' + state + ' (not poweredOn)');
+
+      if (typeof callback === 'function') {
+        callback(error);
+      } else {
+        throw error;
+      }
     } else {
-      throw error;
-    }
-  } else {
-    if (callback) {
-      this.once('scanStart', function(filterDuplicates) {
-        callback(null, filterDuplicates);
-      });
-    }
+      if (callback) {
+        this.once('scanStart', function(filterDuplicates) {
+          callback(null, filterDuplicates);
+        });
+      }
 
-    this._discoveredPeripheralUUids = [];
-    this._allowDuplicates = allowDuplicates;
+      this._discoveredPeripheralUUids = [];
+      this._allowDuplicates = allowDuplicates;
 
-    this._bindings.startScanning(serviceUuids, allowDuplicates);
+      this._bindings.startScanning(serviceUuids, allowDuplicates);
+    }
+  };
+
+  //if bindings still not init, do it now
+  if (!this.initialized) {
+    this._bindings.init();
+    this.initialized = true;
+    this.once('stateChange', scan.bind(this));
+  }else{
+    scan.call(this, this._state);
   }
 };
 
@@ -104,7 +130,9 @@ Noble.prototype.stopScanning = function(callback) {
   if (callback) {
     this.once('scanStop', callback);
   }
-  this._bindings.stopScanning();
+  if(this._bindings && this.initialized){
+    this._bindings.stopScanning();
+  }
 };
 
 Noble.prototype.onScanStop = function() {