wrap a callback bound function in a promise

promise-wrapper.js

// mercilessly culled from npm-promisify
const alreadyAPromise = o => o && typeof o.then === "function" && typeof o.catch === "function";

// As simple as I can get it:
// wrap a function, apply a callback
// return the callback response in Promise.resolve
// 
// NB. This doesn't handle node style err first 
// callbacks with a rejection, but you could...

const press = (original, target) => {

  return (...args) => {

    // todo handle rejection? (😭)
    return new Promise(resolve => {

      // Apply a callback in which we just return
      // whatever is in the response in a resolve()
      args.push(function callback(...values) {
        // todo handle multiple values response
        // as array or not?
        resolve(values[0])
      });

      // Call the function
      const response = original.apply(target, args);

      // If it looks like original already returns a promise,
      // then just resolve with that promise.
      if (alreadyAPromise(response)) {
        resolve(response);
      }
    });
  };
};
// usage...
// press(chrome.windows.getCurrent)().then(resp => {
//   console.log(resp);
// });