poormidi.js

// https://github.com/tadfmac/poormidi
// CCby4.0 D.F.Mac.TripArts Music.

// poormidi.js (Very Poor) Web MIDI API Wrapper
// For Google Chrome Only :D

// 2015.02.23 Change for P&P on Chrome Canary !!!! (W.I.P. and experimental now)
// 2015.06.07 P&P feature has now supported.
// 2015.08.08 add sendCtlChange()
// 2015.08.08 On sendNoteOn(), sendNoteOff() and sendCtlChange(), 
//            arguments are now able to set midi-channel,
//            and also these can be omitted.
//            See also comments in this code, for details.

(function () {

  poormidi = function(){
    this.midi = null;
    this.inputs = [];
    this.outputs = [];
    this.timer = null;

    this.success = function(access){
      console.log("poormidi.success()");
      this.midi = access;
      this.refreshPorts();
      this.midi.onstatechange = this.onStateChange;
    }.bind(this);

    this.failure = function(msg){
      console.log("poormidi.failure(): "+msg);
    }.bind(this);

    this.onMidiEvent = function(e){
      console.log("poormidi.onMidiEvent()");
    }.bind(this);

    this.setHandler = function(func){
      console.log("poormidi.setHandler()");
      this.onMidiEvent = func.bind(this);
    }.bind(this);

    this.sendNoteOn = function(){
      console.log("poormidi.sendNoteOn()");
      var note = 0;
      var velocity = 100;
      var channel = 0;
      if(arguments.length == 1){
        // midi.sendNoteOn(note);
        note = arguments[0];
      }else if(arguments.length == 2){
        // midi.sendNoteOn(note,velocity);
        note = arguments[0];
        velocity = arguments[1];
      }else if(arguments.length == 3){
        // midi.sendNoteOn(channel,note,velocity);
        channel = arguments[0] & 0x0f;
        note = arguments[1];
        velocity = arguments[2];
      }else{
        console.log("poormidi.sendNoteOn:parameter error!!");
        return;
      }  
      if(this.outputs.length > 0){
        for(var cnt=0;cnt<this.outputs.length;cnt++){
          console.log("poormidi.sendNoteOn() output to :"+this.outputs[cnt].name);
          this.outputs[cnt].send([0x90|channel,note&0x7f,velocity&0x7f]);
        }
      }
    }.bind(this);

    this.sendNoteOff = function(){
      console.log("poormidi.sendNoteOff()");
      var note = 0;
      var channel = 0;
      if(arguments.length == 1){
        // midi.sendNoteOff(note);
        note = arguments[0];
      }else if(arguments.length == 2){
        // midi.sendNoteOff(channel,note);
        channel = arguments[0] & 0x0f;
        note = arguments[1];
      }else{
        console.log("poormidi.sendNoteOff:parameter error!!");
        return;
      }  
      if(this.outputs.length > 0){
        for(var cnt=0;cnt<this.outputs.length;cnt++){
          console.log("poormidi.sendNoteOff() output to :"+this.outputs[cnt].name);
          this.outputs[cnt].send([0x80|channel,note,0]);
        }
      }
    }.bind(this);

    this.sendCtlChange = function(){
      console.log("poormidi.sendCtlChange()");
      var channel = 0;
      var number = 0;
      var value = 0;
      if(arguments.length == 2){
        // midi.sendCtlChange(number,value);
        number = arguments[0];
        value = arguments[1];
      }else if(arguments.length == 3){
        // midi.sendCtlChange(channel,number,value);
        channel = arguments[0] & 0x0f;
        number = arguments[1];
        value = arguments[2];
      }else{
        console.log("poormidi.sendCtlChange:parameter error!!");
        return;
      }
      if(this.outputs.length > 0){
        for(var cnt=0;cnt<this.outputs.length;cnt++){
          console.log("poormidi.sendCtlChange() output to :"+this.outputs[cnt].name);
          this.outputs[cnt].send([0xB0|channel,number&0x7f,value&0x7f]);
        }
      }
    }.bind(this);

    this.onStateChange = function(){
      console.log("poormidi.onStateChange()");
      if(this.timer != null){
        clearTimeout(this.timer);
      }
      this.timer = setTimeout(function(){
        this.refreshPorts();
        this.timer = null;
      }.bind(this),300);
    }.bind(this);

    this.refreshPorts = function(){
      console.log("poormidi.refreshPorts()");
      this.inputs = [];
      this.outputs = [];

      // inputs
      var it = this.midi.inputs.values();
      for(var o = it.next(); !o.done; o = it.next()){
        this.inputs.push(o.value);
        console.log("input port: "+o.value.name);
      }
      console.log("poormidi.refreshPorts() inputs: "+this.inputs.length);

      for(var cnt=0;cnt<this.inputs.length;cnt++){
        this.inputs[cnt].onmidimessage = this.onMidiEvent;
      }

      // outputs
      var ot = this.midi.outputs.values();
      for(var o = ot.next(); !o.done; o = ot.next()){
        this.outputs.push(o.value);
        console.log("output port: "+o.value.name);
      }
      console.log("poormidi.refreshPorts() outputs: "+this.outputs.length);

    }.bind(this);

    this.onConnect = function(e){
      console.log("poormidi.onConnect()");
    }
    this.onDisConnect = function(e){
      console.log("poormidi.onDisConnect()");
    }

    navigator.requestMIDIAccess().then(this.success,this.failure);
  };

}).call(this);