@warriorjs/core/lib/loadPlayer.js

WarriorJS core

'use strict';

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

var _assert = require('assert');

var _assert2 = _interopRequireDefault(_assert);

var _vm = require('vm');

var _vm2 = _interopRequireDefault(_vm);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

const playerCodeFilename = 'Player.js';
const playerCodeTimeout = 3000;

/**
 * Loads the player code and returns the playTurn function.
 *
 * @param {string} playerCode The code of the player.
 *
 * @returns {Function} The playTurn function.
 */
function loadPlayer(playerCode) {
  const sandbox = _vm2.default.createContext();

  // Do not collect stack frames for errors in the player code.
  _vm2.default.runInContext('Error.stackTraceLimit = 0;', sandbox);

  try {
    _vm2.default.runInContext(playerCode, sandbox, {
      filename: playerCodeFilename,
      timeout: playerCodeTimeout
    });
  } catch (err) {
    const error = new Error(`Check your syntax and try again!\n\n${err.stack}`);
    error.code = 'InvalidPlayerCode';
    throw error;
  }

  try {
    const player = _vm2.default.runInContext('new Player();', sandbox, {
      timeout: playerCodeTimeout
    });
    (0, _assert2.default)(typeof player.playTurn === 'function', 'playTurn is not defined');
    const playTurn = turn => {
      try {
        player.playTurn(turn);
      } catch (err) {
        const error = new Error(err.message);
        error.code = 'InvalidPlayerCode';
        throw error;
      }
    };
    return playTurn;
  } catch (err) {
    if (err.message === 'Player is not defined') {
      const error = new Error('You must define a Player class!');
      error.code = 'InvalidPlayerCode';
      throw error;
    } else if (err.message === 'playTurn is not defined') {
      const error = new Error('Your Player class must define a playTurn method!');
      error.code = 'InvalidPlayerCode';
      throw error;
    }

    throw err;
  }
}

exports.default = loadPlayer;
module.exports = exports.default;