【备战春招】第8天 破解JavaScript高级玩法 第十五讲

课程名称： 破解JavaScript高级玩法

课程章节： ES高级特性

主讲老师： Cloud

课程内容：

今天学习的内容包括：

ES的高级特性

课程收获：

15.1 心得：

基于装饰器优雅的捕获异常
index.js

const { methodCatch } = require("./methodCatch.js");
const { CatchError } = require("../CatchError");

class DemoClass {

  @methodCatch({ message: "创建订单失败", toast: true, report: true, log: true })
  async createOrder() {
    // a.b();

    throw new CatchError("创建订单失败了，请联系管理员", {
      toast: true,
      report: true,
      log: false
    });
  }
}

const demo = new DemoClass();
demo.createOrder();

methodCatch.js

const { DEFAULT_ERROR_CATCH_OPTIONS } = require("../Const");

const W_TYPES = ["string", "object"];

function methodCatch(options) {
    const type = typeof options;
    let opt;
    if (options == null || !W_TYPES.includes(type)) { // null 或者 不是字符串或者对象
        opt = DEFAULT_ERROR_CATCH_OPTIONS;
    } else if (typeof options === "string") {  // 字符串
        opt = {
            ...DEFAULT_ERROR_CATCH_OPTIONS,
            message: options || DEFAULT_ERROR_CATCH_OPTIONS.message,
        }
    } else { // 有效的对象
        opt = { ...DEFAULT_ERROR_CATCH_OPTIONS, ...options }
    }

    return function (_target, _name, descriptor) {

        // 保存旧的方法
        const oldFn = descriptor.value;
        // 重写旧的方法，
        // 调用自定义的方法，自定义的方法内部再去调用旧的方法
        // descriptor.value = function(){}
        Object.defineProperty(descriptor, "value", {
            get() {
                async function proxy(...args) {
                    try {
                        const res = await oldFn.apply(this, args);
                        return res;
                    } catch (err) {
                        if (err.__type__ == "__CATCH_ERROR__") {
                            console.log(opt, err.options);
                            const mOpt = { ...opt, ...(err.options || {}) };
                            const message = err.message || mOpt.message ;
                            if (mOpt.log) {
                                console.error("asyncMethodCatch:", message, err);
                            }
                            if (mOpt.report) {
                                console.info("report:", message);
                            }

                            if (mOpt.toast) {
                                console.info("toast:", message);
                            }
                        } else {
                            const message = opt.message || err.message;
                            console.error("asyncMethodCatch:", message, err);

                            if (opt.toast) {
                                console.info("toast 输出:", message);
                            }
                        }
                    }
                }
                proxy._bound = true;
                return proxy;
            }
        })
        return descriptor;
    }
}


module.exports = {
    methodCatch
};

proxy

const handler = {

    // 拦截修改属性描述符信息
    // Object.defineProperty()
    // Reflect.defineProperty()，
    // proxy.property='value'
    defineProperty(target, prop, descriptor) {
        console.log('handler:defineProperty');
        return Reflect.defineProperty(target, prop, descriptor);
    },

    // 拦截delete操作
    // delete proxy[property] 和 delete proxy.property
    // Reflect.deleteProperty()
    deleteProperty(target, prop) {
        console.log('handler:deleteProperty');
        return Reflect.deleteProperty(target, prop);
    },

    // 拦截获取属性描述符
    // Object.getOwnPropertyDescriptor()
    // Reflect.getOwnPropertyDescriptor()
    getOwnPropertyDescriptor(target, prop) {
        console.log('handler:getOwnPropertyDescriptor');
        return Reflect.getOwnPropertyDescriptor(target, prop)
    },

    // 拦截in
    // property in proxy
    // 继承属性查询: foo in Object.create(proxy)
    // with 检查: with(proxy) { (property); }
    // Reflect.has()
    has(target, prop) {
        console.log('handler:has');
        return Reflect.has(target, prop);
    },

    // Object.preventExtensions()
    // Reflect.preventExtensions()
    preventExtensions(target) {
        console.log('handler:preventExtensions');
        return Object.preventExtensions(target);
    },

    // Object.isExtensible()
    // Reflect.isExtensible()
    isExtensible(target) {
        console.log('handler:isExtensible');
        return Reflect.isExtensible(target);
        // return true; 也可以return 1;等表示为true的值
    },

    // Object.getOwnPropertyNames()
    // Object.getOwnPropertySymbols()
    // Object.keys()
    // Reflect.ownKeys()
    ownKeys(target) {
        console.log('handler:ownKeys');
        return Reflect.ownKeys(target);
    },
};

const obj = {
    name: "tom",
    age: 18,
    sex: 1
};
const proxyObj = new Proxy(obj, handler);

// defineProperty ，让name不可配置
Object.defineProperty(proxyObj, "name", {
    configurable: false,
})
console.log('\r\n');
//delete 尝试删除
console.log("delete proxyObj.name:", delete proxyObj.name, '\r\n');

// getOwnPropertyDescriptor
console.log("getOwnPropertyDescriptor", Object.getOwnPropertyDescriptor(proxyObj, "name"), '\r\n');

// has
console.log("name in proxyObj:", "name" in proxyObj, '\r\n');

// preventExtensions
Object.preventExtensions(proxyObj);
console.log();

console.log("proxyObj isExtensible:", Object.isExtensible(proxyObj), '\r\n');

// ownKeys
console.log("ownKeys:", Reflect.ownKeys(proxyObj), '\r\n');

不可变数据

/**
 * lodash (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright jQuery Foundation and other contributors <https://jquery.org/>
 * Released under MIT license <https://lodash.com/license>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 */

/** Used as the `TypeError` message for "Functions" methods. */
var FUNC_ERROR_TEXT = 'Expected a function';

/** Used to stand-in for `undefined` hash values. */
var HASH_UNDEFINED = '__lodash_hash_undefined__';

/** Used as references for various `Number` constants. */
var INFINITY = 1 / 0,
    MAX_SAFE_INTEGER = 9007199254740991;

/** `Object#toString` result references. */
var funcTag = '[object Function]',
    genTag = '[object GeneratorFunction]',
    symbolTag = '[object Symbol]';

/** Used to match property names within property paths. */
var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\\]|\\.)*?\1)\]/,
    reIsPlainProp = /^\w*$/,
    reLeadingDot = /^\./,
    rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\\]|\\.)*?)\2)\]|(?=(?:\.|\[\])(?:\.|\[\]|$))/g;

/**
 * Used to match `RegExp`
 * [syntax characters](http://ecma-international.org/ecma-262/7.0/#sec-patterns).
 */
var reRegExpChar = /[\\^$.*+?()[\]{}|]/g;

/** Used to match backslashes in property paths. */
var reEscapeChar = /\\(\\)?/g;

/** Used to detect host constructors (Safari). */
var reIsHostCtor = /^\[object .+?Constructor\]$/;

/** Used to detect unsigned integer values. */
var reIsUint = /^(?:0|[1-9]\d*)$/;

/** Detect free variable `global` from Node.js. */
var freeGlobal = typeof global == 'object' && global && global.Object === Object && global;

/** Detect free variable `self`. */
var freeSelf = typeof self == 'object' && self && self.Object === Object && self;

/** Used as a reference to the global object. */
var root = freeGlobal || freeSelf || Function('return this')();

/**
 * Gets the value at `key` of `object`.
 *
 * @private
 * @param {Object} [object] The object to query.
 * @param {string} key The key of the property to get.
 * @returns {*} Returns the property value.
 */
function getValue(object, key) {
  return object == null ? undefined : object[key];
}

/**
 * Checks if `value` is a host object in IE < 9.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a host object, else `false`.
 */
function isHostObject(value) {
  // Many host objects are `Object` objects that can coerce to strings
  // despite having improperly defined `toString` methods.
  var result = false;
  if (value != null && typeof value.toString != 'function') {
    try {
      result = !!(value + '');
    } catch (e) {}
  }
  return result;
}

/** Used for built-in method references. */
var arrayProto = Array.prototype,
    funcProto = Function.prototype,
    objectProto = Object.prototype;

/** Used to detect overreaching core-js shims. */
var coreJsData = root['__core-js_shared__'];

/** Used to detect methods masquerading as native. */
var maskSrcKey = (function() {
  var uid = /[^.]+$/.exec(coreJsData && coreJsData.keys && coreJsData.keys.IE_PROTO || '');
  return uid ? ('Symbol(src)_1.' + uid) : '';
}());

/** Used to resolve the decompiled source of functions. */
var funcToString = funcProto.toString;

/** Used to check objects for own properties. */
var hasOwnProperty = objectProto.hasOwnProperty;

/**
 * Used to resolve the
 * [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
 * of values.
 */
var objectToString = objectProto.toString;

/** Used to detect if a method is native. */
var reIsNative = RegExp('^' +
  funcToString.call(hasOwnProperty).replace(reRegExpChar, '\\$&')
  .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
);

/** Built-in value references. */
var Symbol = root.Symbol,
    splice = arrayProto.splice;

/* Built-in method references that are verified to be native. */
var Map = getNative(root, 'Map'),
    nativeCreate = getNative(Object, 'create');

/** Used to convert symbols to primitives and strings. */
var symbolProto = Symbol ? Symbol.prototype : undefined,
    symbolToString = symbolProto ? symbolProto.toString : undefined;

/**
 * Creates a hash object.
 *
 * @private
 * @constructor
 * @param {Array} [entries] The key-value pairs to cache.
 */
function Hash(entries) {
  var index = -1,
      length = entries ? entries.length : 0;

  this.clear();
  while (++index < length) {
    var entry = entries[index];
    this.set(entry[0], entry[1]);
  }
}

/**
 * Removes all key-value entries from the hash.
 *
 * @private
 * @name clear
 * @memberOf Hash
 */
function hashClear() {
  this.__data__ = nativeCreate ? nativeCreate(null) : {};
}

/**
 * Removes `key` and its value from the hash.
 *
 * @private
 * @name delete
 * @memberOf Hash
 * @param {Object} hash The hash to modify.
 * @param {string} key The key of the value to remove.
 * @returns {boolean} Returns `true` if the entry was removed, else `false`.
 */
function hashDelete(key) {
  return this.has(key) && delete this.__data__[key];
}

/**
 * Gets the hash value for `key`.
 *
 * @private
 * @name get
 * @memberOf Hash
 * @param {string} key The key of the value to get.
 * @returns {*} Returns the entry value.
 */
function hashGet(key) {
  var data = this.__data__;
  if (nativeCreate) {
    var result = data[key];
    return result === HASH_UNDEFINED ? undefined : result;
  }
  return hasOwnProperty.call(data, key) ? data[key] : undefined;
}

/**
 * Checks if a hash value for `key` exists.
 *
 * @private
 * @name has
 * @memberOf Hash
 * @param {string} key The key of the entry to check.
 * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
 */
function hashHas(key) {
  var data = this.__data__;
  return nativeCreate ? data[key] !== undefined : hasOwnProperty.call(data, key);
}

/**
 * Sets the hash `key` to `value`.
 *
 * @private
 * @name set
 * @memberOf Hash
 * @param {string} key The key of the value to set.
 * @param {*} value The value to set.
 * @returns {Object} Returns the hash instance.
 */
function hashSet(key, value) {
  var data = this.__data__;
  data[key] = (nativeCreate && value === undefined) ? HASH_UNDEFINED : value;
  return this;
}

// Add methods to `Hash`.
Hash.prototype.clear = hashClear;
Hash.prototype['delete'] = hashDelete;
Hash.prototype.get = hashGet;
Hash.prototype.has = hashHas;
Hash.prototype.set = hashSet;

/**
 * Creates an list cache object.
 *
 * @private
 * @constructor
 * @param {Array} [entries] The key-value pairs to cache.
 */
function ListCache(entries) {
  var index = -1,
      length = entries ? entries.length : 0;

  this.clear();
  while (++index < length) {
    var entry = entries[index];
    this.set(entry[0], entry[1]);
  }
}

/**
 * Removes all key-value entries from the list cache.
 *
 * @private
 * @name clear
 * @memberOf ListCache
 */
function listCacheClear() {
  this.__data__ = [];
}

/**
 * Removes `key` and its value from the list cache.
 *
 * @private
 * @name delete
 * @memberOf ListCache
 * @param {string} key The key of the value to remove.
 * @returns {boolean} Returns `true` if the entry was removed, else `false`.
 */
function listCacheDelete(key) {
  var data = this.__data__,
      index = assocIndexOf(data, key);

  if (index < 0) {
    return false;
  }
  var lastIndex = data.length - 1;
  if (index == lastIndex) {
    data.pop();
  } else {
    splice.call(data, index, 1);
  }
  return true;
}

/**
 * Gets the list cache value for `key`.
 *
 * @private
 * @name get
 * @memberOf ListCache
 * @param {string} key The key of the value to get.
 * @returns {*} Returns the entry value.
 */
function listCacheGet(key) {
  var data = this.__data__,
      index = assocIndexOf(data, key);

  return index < 0 ? undefined : data[index][1];
}

/**
 * Checks if a list cache value for `key` exists.
 *
 * @private
 * @name has
 * @memberOf ListCache
 * @param {string} key The key of the entry to check.
 * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
 */
function listCacheHas(key) {
  return assocIndexOf(this.__data__, key) > -1;
}

/**
 * Sets the list cache `key` to `value`.
 *
 * @private
 * @name set
 * @memberOf ListCache
 * @param {string} key The key of the value to set.
 * @param {*} value The value to set.
 * @returns {Object} Returns the list cache instance.
 */
function listCacheSet(key, value) {
  var data = this.__data__,
      index = assocIndexOf(data, key);

  if (index < 0) {
    data.push([key, value]);
  } else {
    data[index][1] = value;
  }
  return this;
}

// Add methods to `ListCache`.
ListCache.prototype.clear = listCacheClear;
ListCache.prototype['delete'] = listCacheDelete;
ListCache.prototype.get = listCacheGet;
ListCache.prototype.has = listCacheHas;
ListCache.prototype.set = listCacheSet;

/**
 * Creates a map cache object to store key-value pairs.
 *
 * @private
 * @constructor
 * @param {Array} [entries] The key-value pairs to cache.
 */
function MapCache(entries) {
  var index = -1,
      length = entries ? entries.length : 0;

  this.clear();
  while (++index < length) {
    var entry = entries[index];
    this.set(entry[0], entry[1]);
  }
}

/**
 * Removes all key-value entries from the map.
 *
 * @private
 * @name clear
 * @memberOf MapCache
 */
function mapCacheClear() {
  this.__data__ = {
    'hash': new Hash,
    'map': new (Map || ListCache),
    'string': new Hash
  };
}

/**
 * Removes `key` and its value from the map.
 *
 * @private
 * @name delete
 * @memberOf MapCache
 * @param {string} key The key of the value to remove.
 * @returns {boolean} Returns `true` if the entry was removed, else `false`.
 */
function mapCacheDelete(key) {
  return getMapData(this, key)['delete'](key);
}

/**
 * Gets the map value for `key`.
 *
 * @private
 * @name get
 * @memberOf MapCache
 * @param {string} key The key of the value to get.
 * @returns {*} Returns the entry value.
 */
function mapCacheGet(key) {
  return getMapData(this, key).get(key);
}

/**
 * Checks if a map value for `key` exists.
 *
 * @private
 * @name has
 * @memberOf MapCache
 * @param {string} key The key of the entry to check.
 * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
 */
function mapCacheHas(key) {
  return getMapData(this, key).has(key);
}

/**
 * Sets the map `key` to `value`.
 *
 * @private
 * @name set
 * @memberOf MapCache
 * @param {string} key The key of the value to set.
 * @param {*} value The value to set.
 * @returns {Object} Returns the map cache instance.
 */
function mapCacheSet(key, value) {
  getMapData(this, key).set(key, value);
  return this;
}

// Add methods to `MapCache`.
MapCache.prototype.clear = mapCacheClear;
MapCache.prototype['delete'] = mapCacheDelete;
MapCache.prototype.get = mapCacheGet;
MapCache.prototype.has = mapCacheHas;
MapCache.prototype.set = mapCacheSet;

/**
 * Assigns `value` to `key` of `object` if the existing value is not equivalent
 * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
 * for equality comparisons.
 *
 * @private
 * @param {Object} object The object to modify.
 * @param {string} key The key of the property to assign.
 * @param {*} value The value to assign.
 */
function assignValue(object, key, value) {
  var objValue = object[key];
  if (!(hasOwnProperty.call(object, key) && eq(objValue, value)) ||
      (value === undefined && !(key in object))) {
    object[key] = value;
  }
}

/**
 * Gets the index at which the `key` is found in `array` of key-value pairs.
 *
 * @private
 * @param {Array} array The array to inspect.
 * @param {*} key The key to search for.
 * @returns {number} Returns the index of the matched value, else `-1`.
 */
function assocIndexOf(array, key) {
  var length = array.length;
  while (length--) {
    if (eq(array[length][0], key)) {
      return length;
    }
  }
  return -1;
}

/**
 * The base implementation of `_.isNative` without bad shim checks.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a native function,
 *  else `false`.
 */
function baseIsNative(value) {
  if (!isObject(value) || isMasked(value)) {
    return false;
  }
  var pattern = (isFunction(value) || isHostObject(value)) ? reIsNative : reIsHostCtor;
  return pattern.test(toSource(value));
}

/**
 * The base implementation of `_.set`.
 *
 * @private
 * @param {Object} object The object to modify.
 * @param {Array|string} path The path of the property to set.
 * @param {*} value The value to set.
 * @param {Function} [customizer] The function to customize path creation.
 * @returns {Object} Returns `object`.
 */
function baseSet(object, path, value, customizer) {
  if (!isObject(object)) {
    return object;
  }
  path = isKey(path, object) ? [path] : castPath(path);

  var index = -1,
      length = path.length,
      lastIndex = length - 1,
      nested = object;

  while (nested != null && ++index < length) {
    var key = toKey(path[index]),
        newValue = value;

    if (index != lastIndex) {
      var objValue = nested[key];
      newValue = customizer ? customizer(objValue, key, nested) : undefined;
      if (newValue === undefined) {
        newValue = isObject(objValue)
          ? objValue
          : (isIndex(path[index + 1]) ? [] : {});
      }
    }
    assignValue(nested, key, newValue);
    nested = nested[key];
  }
  return object;
}

/**
 * The base implementation of `_.toString` which doesn't convert nullish
 * values to empty strings.
 *
 * @private
 * @param {*} value The value to process.
 * @returns {string} Returns the string.
 */
function baseToString(value) {
  // Exit early for strings to avoid a performance hit in some environments.
  if (typeof value == 'string') {
    return value;
  }
  if (isSymbol(value)) {
    return symbolToString ? symbolToString.call(value) : '';
  }
  var result = (value + '');
  return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;
}

/**
 * Casts `value` to a path array if it's not one.
 *
 * @private
 * @param {*} value The value to inspect.
 * @returns {Array} Returns the cast property path array.
 */
function castPath(value) {
  return isArray(value) ? value : stringToPath(value);
}

/**
 * Gets the data for `map`.
 *
 * @private
 * @param {Object} map The map to query.
 * @param {string} key The reference key.
 * @returns {*} Returns the map data.
 */
function getMapData(map, key) {
  var data = map.__data__;
  return isKeyable(key)
    ? data[typeof key == 'string' ? 'string' : 'hash']
    : data.map;
}

/**
 * Gets the native function at `key` of `object`.
 *
 * @private
 * @param {Object} object The object to query.
 * @param {string} key The key of the method to get.
 * @returns {*} Returns the function if it's native, else `undefined`.
 */
function getNative(object, key) {
  var value = getValue(object, key);
  return baseIsNative(value) ? value : undefined;
}

/**
 * Checks if `value` is a valid array-like index.
 *
 * @private
 * @param {*} value The value to check.
 * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
 * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
 */
function isIndex(value, length) {
  length = length == null ? MAX_SAFE_INTEGER : length;
  return !!length &&
    (typeof value == 'number' || reIsUint.test(value)) &&
    (value > -1 && value % 1 == 0 && value < length);
}

/**
 * Checks if `value` is a property name and not a property path.
 *
 * @private
 * @param {*} value The value to check.
 * @param {Object} [object] The object to query keys on.
 * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
 */
function isKey(value, object) {
  if (isArray(value)) {
    return false;
  }
  var type = typeof value;
  if (type == 'number' || type == 'symbol' || type == 'boolean' ||
      value == null || isSymbol(value)) {
    return true;
  }
  return reIsPlainProp.test(value) || !reIsDeepProp.test(value) ||
    (object != null && value in Object(object));
}

/**
 * Checks if `value` is suitable for use as unique object key.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is suitable, else `false`.
 */
function isKeyable(value) {
  var type = typeof value;
  return (type == 'string' || type == 'number' || type == 'symbol' || type == 'boolean')
    ? (value !== '__proto__')
    : (value === null);
}

/**
 * Checks if `func` has its source masked.
 *
 * @private
 * @param {Function} func The function to check.
 * @returns {boolean} Returns `true` if `func` is masked, else `false`.
 */
function isMasked(func) {
  return !!maskSrcKey && (maskSrcKey in func);
}

/**
 * Converts `string` to a property path array.
 *
 * @private
 * @param {string} string The string to convert.
 * @returns {Array} Returns the property path array.
 */
var stringToPath = memoize(function(string) {
  string = toString(string);

  var result = [];
  if (reLeadingDot.test(string)) {
    result.push('');
  }
  string.replace(rePropName, function(match, number, quote, string) {
    result.push(quote ? string.replace(reEscapeChar, '$1') : (number || match));
  });
  return result;
});

/**
 * Converts `value` to a string key if it's not a string or symbol.
 *
 * @private
 * @param {*} value The value to inspect.
 * @returns {string|symbol} Returns the key.
 */
function toKey(value) {
  if (typeof value == 'string' || isSymbol(value)) {
    return value;
  }
  var result = (value + '');
  return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;
}

/**
 * Converts `func` to its source code.
 *
 * @private
 * @param {Function} func The function to process.
 * @returns {string} Returns the source code.
 */
function toSource(func) {
  if (func != null) {
    try {
      return funcToString.call(func);
    } catch (e) {}
    try {
      return (func + '');
    } catch (e) {}
  }
  return '';
}

/**
 * Creates a function that memoizes the result of `func`. If `resolver` is
 * provided, it determines the cache key for storing the result based on the
 * arguments provided to the memoized function. By default, the first argument
 * provided to the memoized function is used as the map cache key. The `func`
 * is invoked with the `this` binding of the memoized function.
 *
 * **Note:** The cache is exposed as the `cache` property on the memoized
 * function. Its creation may be customized by replacing the `_.memoize.Cache`
 * constructor with one whose instances implement the
 * [`Map`](http://ecma-international.org/ecma-262/7.0/#sec-properties-of-the-map-prototype-object)
 * method interface of `delete`, `get`, `has`, and `set`.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Function
 * @param {Function} func The function to have its output memoized.
 * @param {Function} [resolver] The function to resolve the cache key.
 * @returns {Function} Returns the new memoized function.
 * @example
 *
 * var object = { 'a': 1, 'b': 2 };
 * var other = { 'c': 3, 'd': 4 };
 *
 * var values = _.memoize(_.values);
 * values(object);
 * // => [1, 2]
 *
 * values(other);
 * // => [3, 4]
 *
 * object.a = 2;
 * values(object);
 * // => [1, 2]
 *
 * // Modify the result cache.
 * values.cache.set(object, ['a', 'b']);
 * values(object);
 * // => ['a', 'b']
 *
 * // Replace `_.memoize.Cache`.
 * _.memoize.Cache = WeakMap;
 */
function memoize(func, resolver) {
  if (typeof func != 'function' || (resolver && typeof resolver != 'function')) {
    throw new TypeError(FUNC_ERROR_TEXT);
  }
  var memoized = function() {
    var args = arguments,
        key = resolver ? resolver.apply(this, args) : args[0],
        cache = memoized.cache;

    if (cache.has(key)) {
      return cache.get(key);
    }
    var result = func.apply(this, args);
    memoized.cache = cache.set(key, result);
    return result;
  };
  memoized.cache = new (memoize.Cache || MapCache);
  return memoized;
}

// Assign cache to `_.memoize`.
memoize.Cache = MapCache;

/**
 * Performs a
 * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
 * comparison between two values to determine if they are equivalent.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to compare.
 * @param {*} other The other value to compare.
 * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
 * @example
 *
 * var object = { 'a': 1 };
 * var other = { 'a': 1 };
 *
 * _.eq(object, object);
 * // => true
 *
 * _.eq(object, other);
 * // => false
 *
 * _.eq('a', 'a');
 * // => true
 *
 * _.eq('a', Object('a'));
 * // => false
 *
 * _.eq(NaN, NaN);
 * // => true
 */
function eq(value, other) {
  return value === other || (value !== value && other !== other);
}

/**
 * Checks if `value` is classified as an `Array` object.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is an array, else `false`.
 * @example
 *
 * _.isArray([1, 2, 3]);
 * // => true
 *
 * _.isArray(document.body.children);
 * // => false
 *
 * _.isArray('abc');
 * // => false
 *
 * _.isArray(_.noop);
 * // => false
 */
var isArray = Array.isArray;

/**
 * Checks if `value` is classified as a `Function` object.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a function, else `false`.
 * @example
 *
 * _.isFunction(_);
 * // => true
 *
 * _.isFunction(/abc/);
 * // => false
 */
function isFunction(value) {
  // The use of `Object#toString` avoids issues with the `typeof` operator
  // in Safari 8-9 which returns 'object' for typed array and other constructors.
  var tag = isObject(value) ? objectToString.call(value) : '';
  return tag == funcTag || tag == genTag;
}

/**
 * Checks if `value` is the
 * [language type](http://www.ecma-international.org/ecma-262/7.0/#sec-ecmascript-language-types)
 * of `Object`. (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is an object, else `false`.
 * @example
 *
 * _.isObject({});
 * // => true
 *
 * _.isObject([1, 2, 3]);
 * // => true
 *
 * _.isObject(_.noop);
 * // => true
 *
 * _.isObject(null);
 * // => false
 */
function isObject(value) {
  var type = typeof value;
  return !!value && (type == 'object' || type == 'function');
}

/**
 * Checks if `value` is object-like. A value is object-like if it's not `null`
 * and has a `typeof` result of "object".
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
 * @example
 *
 * _.isObjectLike({});
 * // => true
 *
 * _.isObjectLike([1, 2, 3]);
 * // => true
 *
 * _.isObjectLike(_.noop);
 * // => false
 *
 * _.isObjectLike(null);
 * // => false
 */
function isObjectLike(value) {
  return !!value && typeof value == 'object';
}

/**
 * Checks if `value` is classified as a `Symbol` primitive or object.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a symbol, else `false`.
 * @example
 *
 * _.isSymbol(Symbol.iterator);
 * // => true
 *
 * _.isSymbol('abc');
 * // => false
 */
function isSymbol(value) {
  return typeof value == 'symbol' ||
    (isObjectLike(value) && objectToString.call(value) == symbolTag);
}

/**
 * Converts `value` to a string. An empty string is returned for `null`
 * and `undefined` values. The sign of `-0` is preserved.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to process.
 * @returns {string} Returns the string.
 * @example
 *
 * _.toString(null);
 * // => ''
 *
 * _.toString(-0);
 * // => '-0'
 *
 * _.toString([1, 2, 3]);
 * // => '1,2,3'
 */
function toString(value) {
  return value == null ? '' : baseToString(value);
}

/**
 * Sets the value at `path` of `object`. If a portion of `path` doesn't exist,
 * it's created. Arrays are created for missing index properties while objects
 * are created for all other missing properties. Use `_.setWith` to customize
 * `path` creation.
 *
 * **Note:** This method mutates `object`.
 *
 * @static
 * @memberOf _
 * @since 3.7.0
 * @category Object
 * @param {Object} object The object to modify.
 * @param {Array|string} path The path of the property to set.
 * @param {*} value The value to set.
 * @returns {Object} Returns `object`.
 * @example
 *
 * var object = { 'a': [{ 'b': { 'c': 3 } }] };
 *
 * _.set(object, 'a[0].b.c', 4);
 * console.log(object.a[0].b.c);
 * // => 4
 *
 * _.set(object, ['x', '0', 'y', 'z'], 5);
 * console.log(object.x[0].y.z);
 * // => 5
 */
function set(object, path, value) {
  return object == null ? object : baseSet(object, path, value);
}

module.exports = set;