prepost/lib/post.js

Alter arguments and return values before and after a function is called

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = post;

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

var postCallNoop = function postCallNoop(res) {
  return res;
};

// Alter the return value before it is passed back to the caller
function post() {
  var _ref;

  for (var _len = arguments.length, args = Array(_len), _key = 0; _key < _len; _key++) {
    args[_key] = arguments[_key];
  }

  // Flatten args so that pre functions can be passed as arrays
  args = (_ref = []).concat.apply(_ref, _toConsumableArray(args));

  if (args.length < 2) {
    throw new Error('Two arguments required');
  } else if (args.length > 2) {
    args = [post.apply(undefined, _toConsumableArray(args.slice(0, -1))), args[args.length - 1]];
  }

  var callFn = args[0];

  if (typeof callFn !== 'function') {
    throw new TypeError('Function to call must be a function');
  }

  var postFn = args[1] || postCallNoop;

  if (typeof postFn !== 'function') {
    throw new TypeError('Post function must be a function');
  }

  return function () {
    var res = callFn.apply(undefined, arguments);

    // If res is a promise, resolve it before passing it to postFn
    if (res && typeof res.then === 'function') {
      return res.then(postFn);
    }

    return postFn(res);
  };
}