export const isArray = function (a) {
  return (!!a) && (a.constructor === Array);
};

export const isObject = function (a) {
  return (!!a) && (a.constructor === Object);
};

export const isDate = function (o) {
  return o instanceof Object && o.constructor === Date;
}

export const has = function (o, p) {
  let has = true
  for (const prop of p) {
    has = o.hasOwnProperty(prop)
    if (!has) break;
  }
  return has;
}
export const querablePromise = function (promise) {
  // Don't modify any promise that has been already modified.
  if (promise.isPending) return promise;

  // Setup our initial state.
  const state = {
    isPending: true,
    isRejected: false,
    isResolved: false,

    // Specified so that we'll generate accessor functions for them.
    err: undefined,
    val: undefined,
  };

  // We must actually wait for the promise to either resolve or reject,
  // wrap that value, then let it continue on.
  const result = promise.then(
    function (val) {
      state.isResolved = true;
      state.isPending = false;
      state.val = val;
      return val;
    },
    function (err) {
      state.isRejected = true;
      state.isPending = false;
      state.err = err;
      throw err;
    }
  );

  for (const val of Object.keys(state)) {
    result[val] = function () { return state[val]; };
  }

  return result;
}