dodgy/index.js

Optionally abortable, resolvable, and rejectable promises

var dodgy = (function (exports) {
  'use strict';

  function Dodgy(callback, resolvable) {
    var
      resolve, reject, abort,
      status = 'pending',
      dog = new Promise(function (res, rej) {
        callback(
          resolve = function (value) {
            if (status === 'pending') {
              status = 'resolved';
              dog.status = status;
              res(value);
            }
          },
          reject = function (value) {
            if (status === 'pending') {
              status = 'rejected';
              dog.status = status;
              rej(value);
            }
          },
          function onAbort(callback) {
            abort = function (reason) {
              if (status === 'pending') {
                status = 'aborted';
                dog.status = status;
                rej(callback(reason));
              }
            };
          }
        );
      })
    ;
    return evolved(dog, resolvable, abort, resolve, reject);
  }

  function evolved(dog, resolvable, abort, resolve, reject) {
    var
      currentThen = dog.then,
      currentCatch = dog.catch
    ;
    if (abort) dog.abort = abort;
    if (resolvable) {
      dog.resolve = resolve;
      dog.reject = reject;
    }
    dog.then = function () {
      return evolved(
        currentThen.apply(dog, arguments),
        resolvable, abort, resolve, reject
      );
    };
    dog['catch'] = function () {
      return evolved(
        currentCatch.apply(dog, arguments),
        resolvable, abort, resolve, reject
      );
    };
    return dog;
  }

  Dodgy.race = function (iterable) {
    var dog = Promise.race(iterable).then(abort);
    function abort(result) {
      for (var i = 0; i < iterable.length; i++) {
        if ('abort' in iterable[i]) iterable[i].abort();
      }
      return result;
    }
    dog.abort = abort;
    return dog;
  };

  exports.Dodgy = Dodgy;
  exports.default = Dodgy;

  return exports;

}({}));