class-privacy/dist/index.js

Simple way to define private members on ES6 classes, keep their code clean.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports["default"] = void 0;

function _typeof(obj) { if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") { _typeof = function _typeof(obj) { return typeof obj; }; } else { _typeof = function _typeof(obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; }; } return _typeof(obj); }

function isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Date.prototype.toString.call(Reflect.construct(Date, [], function () {})); return true; } catch (e) { return false; } }

function _construct(Parent, args, Class) { if (isNativeReflectConstruct()) { _construct = Reflect.construct; } else { _construct = function _construct(Parent, args, Class) { var a = [null]; a.push.apply(a, args); var Constructor = Function.bind.apply(Parent, a); var instance = new Constructor(); if (Class) _setPrototypeOf(instance, Class.prototype); return instance; }; } return _construct.apply(null, arguments); }

function _setPrototypeOf(o, p) { _setPrototypeOf = Object.setPrototypeOf || function _setPrototypeOf(o, p) { o.__proto__ = p; return o; }; return _setPrototypeOf(o, p); }

/**
 * @type {decide} defaults to a function always returning true
 * @type {revealIsProxy} defaults to false
 * @type {referenceClass} defaults to false
 */
var defaultOptions = {};

defaultOptions.decide = function () {
  return true;
};

defaultOptions.revealIsProxy = false;
defaultOptions.referenceClass = false;
var IS_PROXY = 'isProxy';
var CLASS = 'class';
/**
 * @private checks for a prototype constructor to match an expected value
 */

var check = function check(value, expected) {
  var proto = value && Object.getPrototypeOf(value);
  var constructor = proto && proto.constructor;

  if (constructor !== expected) {
    var constructorName = constructor && constructor.name;
    var expectedName = expected && expected.name;
    throw new TypeError("Expected ".concat(expectedName, ", got ").concat(constructorName, "."));
  }
};
/**
 * Creates a factory function that produces proxies to instances of a {class} definition, based on
 * @param ClassDefinition
 * @param options.decide {function} A function that checks the instance's given {key} and {value} of a property and
 *        returns true, if the property is public or false if private.
 * @param options.revealIsProxy {boolean} if true it allows external code to ask for {isProxy} which then returns true
 * @param options.referenceClass {boolean} if true it allows external code to ask for {class} which then returns
 *        the referenced original class definition but never the instance
 * @returns {function} A factory function to produce proxies to an instance
 */


var createFactory = function createFactory(ClassDefinition) {
  var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : defaultOptions;
  check(ClassDefinition, Function);
  check(options, Object); // we flat-merge the options with the default options
  // to ensure that there are no options missing and the factory
  // doesn't crash at runtime, for example because an options has
  // been explicitly set to null

  var factoryOptions = Object.assign({}, defaultOptions, options);
  var decide = factoryOptions.decide || defaultOptions.decide;
  var referenceClass = factoryOptions.referenceClass || defaultOptions.referenceClass;
  var revealIsProxy = factoryOptions.revealIsProxy || defaultOptions.revealIsProxy;
  /**
   * Creates an instance of the given ClassDefinition
   * @param invocationArgs arguments of arbitrary length, determined by ClassDefinition
   * @return {proxy}
   */

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

    var instance = _construct(ClassDefinition, invocationArgs);

    var handler = {
      get: function get(target, property
      /*, receiver */
      ) {
        // get proxy by symbol
        if (revealIsProxy && property === IS_PROXY) {
          return true;
        } // get class by symbol


        if (referenceClass && property === CLASS) {
          return ClassDefinition;
        } // skip any request to unowned properties
        // using 'in' as a good trade-off between validity and performance


        if (!(property in instance)) {
          return;
        } // skip members, that don't pass the test,
        // let developer decide how to design tests


        var member = instance[property];

        var type = _typeof(member);

        var includeMember = decide(property, type, ClassDefinition);

        if (!includeMember) {
          return;
        } // bind functions to the instance to avoid unintended
        // blocking the member function's internals


        if (type === 'function') {
          return member.bind(instance);
        } else {
          return member;
        }
      }
    };
    return new Proxy({}, handler);
  };

  return factory;
};

var _default = createFactory;
exports["default"] = _default;
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