【备战春招】第8天 破解JavaScript高级玩法 第十五讲
标签：
JavaScript
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;
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