lodash/lodash._stack/index.js

/**
 * lodash 4.1.1 (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright 2012-2016 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2016 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */

/** Used as the size to enable large array optimizations. */
var LARGE_ARRAY_SIZE = 200;

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

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

/** 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 > 5). */
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 free variable `global` from Node.js. */
var freeGlobal = checkGlobal(freeExports && freeModule && typeof global == 'object' && global);

/** Detect free variable `self`. */
var freeSelf = checkGlobal(objectTypes[typeof self] && self);

/** Detect free variable `window`. */
var freeWindow = checkGlobal(objectTypes[typeof window] && window);

/** Detect `this` as the global object. */
var thisGlobal = checkGlobal(objectTypes[typeof this] && this);

/**
 * Used as a reference to the global object.
 *
 * The `this` value is used if it's the global object to avoid Greasemonkey's
 * restricted `window` object, otherwise the `window` object is used.
 */
var root = freeGlobal ||
  ((freeWindow !== (thisGlobal && thisGlobal.window)) && freeWindow) ||
    freeSelf || thisGlobal || Function('return this')();

/**
 * Checks if `value` is a global object.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {null|Object} Returns `value` if it's a global object, else `null`.
 */
function checkGlobal(value) {
  return (value && value.Object === Object) ? value : null;
}

/**
 * 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,
    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 splice = arrayProto.splice;

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

/**
 * Creates an hash object.
 *
 * @private
 * @constructor
 * @returns {Object} Returns the new hash object.
 */
function Hash() {}

/**
 * Removes `key` and its value from the hash.
 *
 * @private
 * @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(hash, key) {
  return hashHas(hash, key) && delete hash[key];
}

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

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

/**
 * Sets the hash `key` to `value`.
 *
 * @private
 * @param {Object} hash The hash to modify.
 * @param {string} key The key of the value to set.
 * @param {*} value The value to set.
 */
function hashSet(hash, key, value) {
  hash[key] = (nativeCreate && value === undefined) ? HASH_UNDEFINED : value;
}

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

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

/**
 * Removes all key-value entries from the map.
 *
 * @private
 * @name clear
 * @memberOf MapCache
 */
function mapClear() {
  this.__data__ = {
    'hash': new Hash,
    'map': Map ? new Map : [],
    '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 mapDelete(key) {
  var data = this.__data__;
  if (isKeyable(key)) {
    return hashDelete(typeof key == 'string' ? data.string : data.hash, key);
  }
  return Map ? data.map['delete'](key) : assocDelete(data.map, 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 mapGet(key) {
  var data = this.__data__;
  if (isKeyable(key)) {
    return hashGet(typeof key == 'string' ? data.string : data.hash, key);
  }
  return Map ? data.map.get(key) : assocGet(data.map, 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 mapHas(key) {
  var data = this.__data__;
  if (isKeyable(key)) {
    return hashHas(typeof key == 'string' ? data.string : data.hash, key);
  }
  return Map ? data.map.has(key) : assocHas(data.map, 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 object.
 */
function mapSet(key, value) {
  var data = this.__data__;
  if (isKeyable(key)) {
    hashSet(typeof key == 'string' ? data.string : data.hash, key, value);
  } else if (Map) {
    data.map.set(key, value);
  } else {
    assocSet(data.map, key, value);
  }
  return this;
}

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

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

/**
 * Removes all key-value entries from the stack.
 *
 * @private
 * @name clear
 * @memberOf Stack
 */
function stackClear() {
  this.__data__ = { 'array': [], 'map': null };
}

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

  return array ? assocDelete(array, key) : data.map['delete'](key);
}

/**
 * Gets the stack value for `key`.
 *
 * @private
 * @name get
 * @memberOf Stack
 * @param {string} key The key of the value to get.
 * @returns {*} Returns the entry value.
 */
function stackGet(key) {
  var data = this.__data__,
      array = data.array;

  return array ? assocGet(array, key) : data.map.get(key);
}

/**
 * Checks if a stack value for `key` exists.
 *
 * @private
 * @name has
 * @memberOf Stack
 * @param {string} key The key of the entry to check.
 * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
 */
function stackHas(key) {
  var data = this.__data__,
      array = data.array;

  return array ? assocHas(array, key) : data.map.has(key);
}

/**
 * Sets the stack `key` to `value`.
 *
 * @private
 * @name set
 * @memberOf Stack
 * @param {string} key The key of the value to set.
 * @param {*} value The value to set.
 * @returns {Object} Returns the stack cache object.
 */
function stackSet(key, value) {
  var data = this.__data__,
      array = data.array;

  if (array) {
    if (array.length < (LARGE_ARRAY_SIZE - 1)) {
      assocSet(array, key, value);
    } else {
      data.array = null;
      data.map = new MapCache(array);
    }
  }
  var map = data.map;
  if (map) {
    map.set(key, value);
  }
  return this;
}

/**
 * Removes `key` and its value from the associative array.
 *
 * @private
 * @param {Array} array The array to query.
 * @param {string} key The key of the value to remove.
 * @returns {boolean} Returns `true` if the entry was removed, else `false`.
 */
function assocDelete(array, key) {
  var index = assocIndexOf(array, key);
  if (index < 0) {
    return false;
  }
  var lastIndex = array.length - 1;
  if (index == lastIndex) {
    array.pop();
  } else {
    splice.call(array, index, 1);
  }
  return true;
}

/**
 * Gets the associative array value for `key`.
 *
 * @private
 * @param {Array} array The array to query.
 * @param {string} key The key of the value to get.
 * @returns {*} Returns the entry value.
 */
function assocGet(array, key) {
  var index = assocIndexOf(array, key);
  return index < 0 ? undefined : array[index][1];
}

/**
 * Checks if an associative array value for `key` exists.
 *
 * @private
 * @param {Array} array The array to query.
 * @param {string} key The key of the entry to check.
 * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
 */
function assocHas(array, key) {
  return assocIndexOf(array, key) > -1;
}

/**
 * Gets the index at which the first occurrence of `key` is found in `array`
 * of key-value pairs.
 *
 * @private
 * @param {Array} array The array to search.
 * @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;
}

/**
 * Sets the associative array `key` to `value`.
 *
 * @private
 * @param {Array} array The array to modify.
 * @param {string} key The key of the value to set.
 * @param {*} value The value to set.
 */
function assocSet(array, key, value) {
  var index = assocIndexOf(array, key);
  if (index < 0) {
    array.push([key, value]);
  } else {
    array[index][1] = value;
  }
}

/**
 * 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;
}

/**
 * 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 == 'number' || type == 'boolean' ||
    (type == 'string' && value != '__proto__') || value == null;
}

/**
 * Performs a [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
 * comparison between two values to determine if they are equivalent.
 *
 * @static
 * @memberOf _
 * @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 = { 'user': 'fred' };
 * var other = { 'user': 'fred' };
 *
 * _.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 a `Function` object.
 *
 * @static
 * @memberOf _
 * @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 the [language type](https://es5.github.io/#x8) of `Object`.
 * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
 *
 * @static
 * @memberOf _
 * @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 _
 * @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 _
 * @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);
}

// Avoid inheriting from `Object.prototype` when possible.
Hash.prototype = nativeCreate ? nativeCreate(null) : objectProto;

// Add functions to the `MapCache`.
MapCache.prototype.clear = mapClear;
MapCache.prototype['delete'] = mapDelete;
MapCache.prototype.get = mapGet;
MapCache.prototype.has = mapHas;
MapCache.prototype.set = mapSet;

// Add functions to the `Stack` cache.
Stack.prototype.clear = stackClear;
Stack.prototype['delete'] = stackDelete;
Stack.prototype.get = stackGet;
Stack.prototype.has = stackHas;
Stack.prototype.set = stackSet;

module.exports = Stack;