Alternatives to async provision

gistfile1.js

var HelloApp = module.exports = function() {
  this.name = 'hello';
};

HelloApp.prototype.init = function(fog) {
  fog.provision('photosensor', function(photosensor){
    photosensor.on('change', function(value) {
      if (value < 100) {
        led.call('turn-on');
      } else {
        led.call('turn-off');
      }
      
      fog.expose('/photosensor', photosensor);
    });
    
  });
  
  
  fog.provision('led', function(led){
    led.on('turn-on', function() {
      console.log('turning on led');
    });
  
    led.on('turn-off', function() {
      console.log('turning off led');
    });
  
    fog.expose('/led', led);
  });
};

gistfile2.js

var HelloApp = module.exports = function() {
  this.name = 'hello';
};

HelloApp.prototype.init = function(fog) {
  var photosensor = fog.provision('photosensor');
  var led = fog.provision('led');


  led.on('ready', function() {
    led.on('turn-on', function() {
      console.log('turning on led');
    });
  
    led.on('turn-off', function() {
      console.log('turning off led');
    });
    
    fog.expose('/led', led);
  });

  photosensor.on('ready', function() {
  
    photosensor.on('change', function(value) {
      if (value < 100) {
        led.call('turn-on');
      } else {
        led.call('turn-off');
      }
    });
    
    fog.expose('/photosensor', photosensor);
  });
};

gistfile3.js

var HelloApp = module.exports = function() {
  this.name = 'hello';
};

HelloApp.prototype.init = function(fog) {

  fog.provision('photosensor');
  fog.provision('led');

  HelloApp.on('ready', function(photosensor, led) {
    led.on('turn-on', function() {
      console.log('turning on led');
    });
  
    led.on('turn-off', function() {
      console.log('turning off led');
    });
  
    photosensor.on('change', function(value) {
      if (value < 100) {
        led.call('turn-on');
      } else {
        led.call('turn-off');
      }
    });
  
    fog.expose('/led', led);
    fog.expose('/photosensor', photosensor);
  });
};

gistfile4.js

var HelloApp = module.exports = function() {
  this.name = 'hello';
  this.photosensor = fog.provision('photosensor');
  this.led = fog.provision('led');
};

HelloApp.prototype.ready = function(fog) {

    this.led.on('turn-on', function() {
      console.log('turning on led');
    });
  
    this.led.on('turn-off', function() {
      console.log('turning off led');
    });
  
    this.photosensor.on('change', function(value) {
      if (value < 100) {
        this.led.call('turn-on');
      } else {
        this.led.call('turn-off');
      }
    });
  
    fog.expose('/led', this.led);
    fog.expose('/photosensor', this.photosensor);
};

Another option:

var HelloApp = module.exports = function() {
  this.name = 'hello';
};

HelloApp.prototype.init = function(fog) {
  fog.provision(['photosensor', 'led'], function(photosensor, led) {
    led.on('turn-on', function() {
      console.log('turning on led');
    });

    led.on('turn-off', function() {
      console.log('turning off led');
    });

    photosensor.on('change', function(value) {
      if (value < 100) {
        led.call('turn-on');
      } else {
        led.call('turn-off');
      }
    });

    fog.expose('/photosensor', photosensor);
    fog.expose('/led', led);
  });
};

Settled on this:

module.exports = function(app) {
  app
    .use('office-bridge');
    .on('ready', function() {
      var bridge = app.devices['office-bridge'];
      app.expose(bridge);

      bridge.on('light:ready', function(light) {
        light.call('set-color', 'red');
      });
    });
};

module.exports = function(elroy) {
  elroy.get('photosensor', function(err, photosensor) {
    elroy.get('led', function(err, led) {
      led.on('turn-on', function() {
        console.log('on');
      });

      led.on('turn-off', function() {
        console.log('off');
      });

      photosensor.on('change', function(value) {
        if (value < 100) {
          led.call('turn-on');
        } else {
          led.call('turn-off');
        }
      });

      led.on('error', function(err) {
        if (typeof err !== elroy.TransitionError) {
          throw err;
        }
      });

      elroy.expose(led);
    });

    elroy.expose(photosensor);
  });
};