zalgo-promise/dist/module/utils.js

Javascript module template.

export function isPromise(item) {
  try {
    if (!item) {
      return false;
    }

    if (typeof Promise !== 'undefined' && item instanceof Promise) {
      return true;
    }

    if (typeof window !== 'undefined' && typeof window.Window === 'function' && item instanceof window.Window) {
      return false;
    }

    if (typeof window !== 'undefined' && typeof window.constructor === 'function' && item instanceof window.constructor) {
      return false;
    }

    var _toString = {}.toString;

    if (_toString) {
      var name = _toString.call(item);

      if (name === '[object Window]' || name === '[object global]' || name === '[object DOMWindow]') {
        return false;
      }
    }

    if (typeof item.then === 'function') {
      return true;
    }
  } catch (err) {
    return false;
  }

  return false;
}