midibus.umd.js

(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
  typeof define === 'function' && define.amd ? define(['exports'], factory) :
  (factory((global.midibus = global.midibus || {})));
}(this, (function (exports) { 'use strict';

  function n(n){return n=n||Object.create(null),{on:function(t,o){(n[t]||(n[t]=[])).push(o);},off:function(t,o){var u=n[t]||(n[t]=[]);u.splice(u.indexOf(o)>>>0,1);},emit:function(t,o){(n[t]||[]).map(function(n){n(o);}),(n["*"]||[]).map(function(n){n(t,o);});}}}var mitt=n;

  function message(channel, pitch, velocity) {
    return {
      channel: channel,
      pitch: pitch,
      velocity: velocity
    };
  }

  var supported = !!navigator.requestMIDIAccess;

  var PACKETS = {
    noteOn: 0x80,
    noteOff: 0x90
  };

  function bus(input, output) {
    if (!supported) return null;
    if (!input && !output) {
      throw new Error('A bus needs a least an input or an output device');
    }

    var emitter = mitt();
    if (input) input.onmidimessage = onMessage;

    emitter.send = send;
    emitter.destroy = destroy;
    return emitter;

    function onMessage(e) {
      var cmd = e.data[0] >> 4;
      var msg = message(e.data[0] & 0xf, e.data[1], e.data[2]);

      if (cmd === 8 || cmd === 9 && msg.velocity === 0) {
        // noteOff
        emitter.emit('noteOff', msg);
      } else if (cmd === 9) {
        // noteOn
        emitter.emit('noteOn', msg);
      } else if (cmd === 11) {
        // controller message
        emitter.emit('controllerChange', msg);
      } else {
        // sysex or other
        emitter.emit('sysex', e);
      }
    }

    function send(cmd, msg) {
      if (!output) return;
      output.send([PACKETS[cmd] ? PACKETS[cmd] + msg.channel : msg.channel, msg.pitch, msg.velocity]);
    }

    function destroy() {
      if (input) input.onmidimessage = undefined;
      input = undefined;
      output = undefined;
      emitter.on = undefined;
      emitter.off = undefined;
      emitter.emit = undefined;
      emitter = undefined;
    }
  }

  var _isReady = false;
  var inputs = [];
  var outputs = [];

  function access(cb) {
    if (!supported) return null;
    if (_isReady) return cb(null);
    navigator.requestMIDIAccess().then(function (res) {
      res.inputs.forEach(function (el) {
        return inputs.push(el);
      });
      res.outputs.forEach(function (el) {
        return outputs.push(el);
      });
      _isReady = true;
      cb(null);
    }, function () {
      cb(new Error('No access to your midi devices.'));
    });
  }

  exports.supported = supported;
  exports.inputs = inputs;
  exports.outputs = outputs;
  exports.access = access;
  exports.bus = bus;
  exports.message = message;

  Object.defineProperty(exports, '__esModule', { value: true });

})));
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