{
  "name": "midi-editor",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "dependencies": {
    "concat-stream": "^1.4.6",
    "hut-modal": "^0.1.1",
    "level-js": "^2.1.6",
    "levelup": "^0.19.0",
    "midimal": "^0.0.7",
    "midifile": "^0.2.0",
    "leveljs": "^0.0.0-a1",
    "midistream": "^0.1.0",
    "midiplayer": "^0.0.1"
  },
  "devDependencies": {},
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Eduardo Sorribas <eduardo@sorribas.org> (http://sorribas.org/)",
  "license": "MIT"
}

{
  "name": "midi-editor",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "dependencies": {
    "concat-stream": "^1.4.6",
    "hut-modal": "^0.1.1",
    "level-js": "^2.1.6",
    "levelup": "^0.19.0",
    "midimal": "^0.0.7",
    "midifile": "^0.2.0",
    "leveljs": "^0.0.0-a1",
    "midistream": "^0.1.0",
    "midiplayer": "^0.0.1"
  },
  "devDependencies": {
    "browserify": "^7.0.0"
  },
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "build": "browserify index.js > bundle.js"
  },
  "author": "Eduardo Sorribas <eduardo@sorribas.org> (http://sorribas.org/)",
  "license": "MIT"
}

Add browserify as a dev dependency and added build script.
Add browserify as a dev dependency and added build script.