> I don't know how to publish this package in a way all JS transpilers and bundlers out there can understand. Please help me.

Don't do this:

    module.exports = IPFSDropzone

Do this (and change documentation accordingly)

    module.exports = {IPFSDropzone}

or to go full ES6 do this

    export {IPFSDropzone};

add the package babel-env and add this script to package.json:

    "scripts": {
      "prepublish": "node node_modules/babel-cli/bin/babel *.js -d build/"
    },

and change main to "build/index.js".

Run "npm run prepublish" to test.

Edit: Now that I think of it, compiling with babel is probably unnecessary. But it doesn't hurt and can help old setups.