/**
 * lodash 4.2.0 (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
 */
var keys = require('lodash.keys'),
    root = require('lodash._root');

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

/** `Object#toString` result references. */
var argsTag = '[object Arguments]',
    funcTag = '[object Function]',
    genTag = '[object GeneratorFunction]',
    mapTag = '[object Map]',
    objectTag = '[object Object]',
    promiseTag = '[object Promise]',
    setTag = '[object Set]',
    stringTag = '[object String]',
    weakMapTag = '[object WeakMap]';

var dataViewTag = '[object DataView]';

/** Used to match `RegExp` [syntax characters](http://ecma-international.org/ecma-262/6.0/#sec-patterns). */
var reRegExpChar = /[\\^$.*+?()[\]{}|]/g;

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

/** Used to determine if values are of the language type `Object`. */
var objectTypes = {
  'function': true,
  'object': true
};

/** Detect free variable `exports`. */
var freeExports = (objectTypes[typeof exports] && exports && !exports.nodeType)
  ? exports
  : undefined;

/** Detect free variable `module`. */
var freeModule = (objectTypes[typeof module] && module && !module.nodeType)
  ? module
  : undefined;

/** Detect the popular CommonJS extension `module.exports`. */
var moduleExports = (freeModule && freeModule.exports === freeExports)
  ? freeExports
  : undefined;

/**
 * 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 objectProto = Object.prototype;

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

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

/**
 * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#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 Buffer = moduleExports ? root.Buffer : undefined,
    propertyIsEnumerable = objectProto.propertyIsEnumerable;

/* Built-in method references that are verified to be native. */
var DataView = getNative(root, 'DataView'),
    Map = getNative(root, 'Map'),
    Promise = getNative(root, 'Promise'),
    Set = getNative(root, 'Set'),
    WeakMap = getNative(root, 'WeakMap');

/** Detect if properties shadowing those on `Object.prototype` are non-enumerable. */
var nonEnumShadows = !propertyIsEnumerable.call({ 'valueOf': 1 }, 'valueOf');

/** Used to detect maps, sets, and weakmaps. */
var dataViewCtorString = DataView ? (DataView + '') : '',
    mapCtorString = Map ? funcToString.call(Map) : '',
    promiseCtorString = Promise ? funcToString.call(Promise) : '',
    setCtorString = Set ? funcToString.call(Set) : '',
    weakMapCtorString = WeakMap ? funcToString.call(WeakMap) : '';

/**
 * The base implementation of `_.property` without support for deep paths.
 *
 * @private
 * @param {string} key The key of the property to get.
 * @returns {Function} Returns the new function.
 */
function baseProperty(key) {
  return function(object) {
    return object == null ? undefined : object[key];
  };
}

/**
 * Gets the "length" property value of `object`.
 *
 * **Note:** This function is used to avoid a
 * [JIT bug](https://bugs.webkit.org/show_bug.cgi?id=142792) that affects
 * Safari on at least iOS 8.1-8.3 ARM64.
 *
 * @private
 * @param {Object} object The object to query.
 * @returns {*} Returns the "length" value.
 */
var getLength = baseProperty('length');

/**
 * 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 = object[key];
  return isNative(value) ? value : undefined;
}

/**
 * Gets the `toStringTag` of `value`.
 *
 * @private
 * @param {*} value The value to query.
 * @returns {string} Returns the `toStringTag`.
 */
function getTag(value) {
  return objectToString.call(value);
}

// Fallback for data views, maps, sets, and weak maps in IE 11,
// for data views in Edge, and promises in Node.js.
if ((DataView && getTag(new DataView(new ArrayBuffer(1))) != dataViewTag) ||
    (Map && getTag(new Map) != mapTag) ||
    (Promise && getTag(Promise.resolve()) != promiseTag) ||
    (Set && getTag(new Set) != setTag) ||
    (WeakMap && getTag(new WeakMap) != weakMapTag)) {
  getTag = function(value) {
    var result = objectToString.call(value),
        Ctor = result == objectTag ? value.constructor : null,
        ctorString = typeof Ctor == 'function' ? funcToString.call(Ctor) : '';

    if (ctorString) {
      switch (ctorString) {
        case dataViewCtorString: return dataViewTag;
        case mapCtorString: return mapTag;
        case promiseCtorString: return promiseTag;
        case setCtorString: return setTag;
        case weakMapCtorString: return weakMapTag;
      }
    }
    return result;
  };
}

/**
 * Checks if `value` is likely an `arguments` object.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is correctly classified,
 *  else `false`.
 * @example
 *
 * _.isArguments(function() { return arguments; }());
 * // => true
 *
 * _.isArguments([1, 2, 3]);
 * // => false
 */
function isArguments(value) {
  // Safari 8.1 incorrectly makes `arguments.callee` enumerable in strict mode.
  return isArrayLikeObject(value) && hasOwnProperty.call(value, 'callee') &&
    (!propertyIsEnumerable.call(value, 'callee') || objectToString.call(value) == argsTag);
}

/**
 * Checks if `value` is classified as an `Array` object.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @type {Function}
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is correctly classified,
 *  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 array-like. A value is considered array-like if it's
 * not a function and has a `value.length` that's an integer greater than or
 * equal to `0` and less than or equal to `Number.MAX_SAFE_INTEGER`.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is array-like, else `false`.
 * @example
 *
 * _.isArrayLike([1, 2, 3]);
 * // => true
 *
 * _.isArrayLike(document.body.children);
 * // => true
 *
 * _.isArrayLike('abc');
 * // => true
 *
 * _.isArrayLike(_.noop);
 * // => false
 */
function isArrayLike(value) {
  return value != null && isLength(getLength(value)) && !isFunction(value);
}

/**
 * This method is like `_.isArrayLike` except that it also checks if `value`
 * is an object.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is an array-like object,
 *  else `false`.
 * @example
 *
 * _.isArrayLikeObject([1, 2, 3]);
 * // => true
 *
 * _.isArrayLikeObject(document.body.children);
 * // => true
 *
 * _.isArrayLikeObject('abc');
 * // => false
 *
 * _.isArrayLikeObject(_.noop);
 * // => false
 */
function isArrayLikeObject(value) {
  return isObjectLike(value) && isArrayLike(value);
}

/**
 * Checks if `value` is a buffer.
 *
 * @static
 * @memberOf _
 * @since 4.3.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a buffer, else `false`.
 * @example
 *
 * _.isBuffer(new Buffer(2));
 * // => true
 *
 * _.isBuffer(new Uint8Array(2));
 * // => false
 */
var isBuffer = !Buffer ? constant(false) : function(value) {
  return value instanceof Buffer;
};

/**
 * Checks if `value` is an empty object, collection, map, or set.
 *
 * Objects are considered empty if they have no own enumerable string keyed
 * properties.
 *
 * Array-like values such as `arguments` objects, arrays, buffers, strings, or
 * jQuery-like collections are considered empty if they have a `length` of `0`.
 * Similarly, maps and sets are considered empty if they have a `size` of `0`.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is empty, else `false`.
 * @example
 *
 * _.isEmpty(null);
 * // => true
 *
 * _.isEmpty(true);
 * // => true
 *
 * _.isEmpty(1);
 * // => true
 *
 * _.isEmpty([1, 2, 3]);
 * // => false
 *
 * _.isEmpty({ 'a': 1 });
 * // => false
 */
function isEmpty(value) {
  if (isArrayLike(value) &&
      (isArray(value) || isString(value) || isFunction(value.splice) ||
        isArguments(value) || isBuffer(value))) {
    return !value.length;
  }
  if (isObjectLike(value)) {
    var tag = getTag(value);
    if (tag == mapTag || tag == setTag) {
      return !value.size;
    }
  }
  for (var key in value) {
    if (hasOwnProperty.call(value, key)) {
      return false;
    }
  }
  return !(nonEnumShadows && keys(value).length);
}

/**
 * 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 correctly classified,
 *  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 which returns 'object' for typed array and weak map constructors,
  // and PhantomJS 1.9 which returns 'function' for `NodeList` instances.
  var tag = isObject(value) ? objectToString.call(value) : '';
  return tag == funcTag || tag == genTag;
}

/**
 * Checks if `value` is a valid array-like length.
 *
 * **Note:** This function is loosely based on
 * [`ToLength`](http://ecma-international.org/ecma-262/6.0/#sec-tolength).
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a valid length,
 *  else `false`.
 * @example
 *
 * _.isLength(3);
 * // => true
 *
 * _.isLength(Number.MIN_VALUE);
 * // => false
 *
 * _.isLength(Infinity);
 * // => false
 *
 * _.isLength('3');
 * // => false
 */
function isLength(value) {
  return typeof value == 'number' &&
    value > -1 && value % 1 == 0 && value <= MAX_SAFE_INTEGER;
}

/**
 * Checks if `value` is the [language type](https://es5.github.io/#x8) 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 a native function.
 *
 * @static
 * @memberOf _
 * @since 3.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a native function,
 *  else `false`.
 * @example
 *
 * _.isNative(Array.prototype.push);
 * // => true
 *
 * _.isNative(_);
 * // => false
 */
function isNative(value) {
  if (value == null) {
    return false;
  }
  if (isFunction(value)) {
    return reIsNative.test(funcToString.call(value));
  }
  return isObjectLike(value) &&
    (isHostObject(value) ? reIsNative : reIsHostCtor).test(value);
}

/**
 * Checks if `value` is classified as a `String` primitive or object.
 *
 * @static
 * @since 0.1.0
 * @memberOf _
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is correctly classified,
 *  else `false`.
 * @example
 *
 * _.isString('abc');
 * // => true
 *
 * _.isString(1);
 * // => false
 */
function isString(value) {
  return typeof value == 'string' ||
    (!isArray(value) && isObjectLike(value) && objectToString.call(value) == stringTag);
}

/**
 * Creates a function that returns `value`.
 *
 * @static
 * @memberOf _
 * @since 2.4.0
 * @category Util
 * @param {*} value The value to return from the new function.
 * @returns {Function} Returns the new function.
 * @example
 *
 * var object = { 'user': 'fred' };
 * var getter = _.constant(object);
 *
 * getter() === object;
 * // => true
 */
function constant(value) {
  return function() {
    return value;
  };
}

module.exports = isEmpty;