Edit: underscore.js

// Underscore.js 1.8.3 // http://underscorejs.org // (c) 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors // Underscore may be freely distributed under the MIT license. (function() { // Baseline setup // -------------- // Establish the root object, `window` in the browser, or `exports` on the server. var root = this; // Save the previous value of the `_` variable. var previousUnderscore = root._; // Save bytes in the minified (but not gzipped) version: var ArrayProto = Array.prototype, ObjProto = Object.prototype, FuncProto = Function.prototype; // Create quick reference variables for speed access to core prototypes. var push = ArrayProto.push, slice = ArrayProto.slice, toString = ObjProto.toString, hasOwnProperty = ObjProto.hasOwnProperty; // All **ECMAScript 5** native function implementations that we hope to use // are declared here. var nativeIsArray = Array.isArray, nativeKeys = Object.keys, nativeBind = FuncProto.bind, nativeCreate = Object.create; // Naked function reference for surrogate-prototype-swapping. var Ctor = function(){}; // Create a safe reference to the Underscore object for use below. var _ = function(obj) { if (obj instanceof _) return obj; if (!(this instanceof _)) return new _(obj); this._wrapped = obj; }; // Export the Underscore object for **Node.js**, with // backwards-compatibility for the old `require()` API. If we're in // the browser, add `_` as a global object. if (typeof exports !== 'undefined') { if (typeof module !== 'undefined' && module.exports) { exports = module.exports = _; } exports._ = _; } else { root._ = _; } // Current version. _.VERSION = '1.8.3'; // Internal function that returns an efficient (for current engines) version // of the passed-in callback, to be repeatedly applied in other Underscore // functions. var optimizeCb = function(func, context, argCount) { if (context === void 0) return func; switch (argCount == null ? 3 : argCount) { case 1: return function(value) { return func.call(context, value); }; case 2: return function(value, other) { return func.call(context, value, other); }; case 3: return function(value, index, collection) { return func.call(context, value, index, collection); }; case 4: return function(accumulator, value, index, collection) { return func.call(context, accumulator, value, index, collection); }; } return function() { return func.apply(context, arguments); }; }; // A mostly-internal function to generate callbacks that can be applied // to each element in a collection, returning the desired result — either // identity, an arbitrary callback, a property matcher, or a property accessor. var cb = function(value, context, argCount) { if (value == null) return _.identity; if (_.isFunction(value)) return optimizeCb(value, context, argCount); if (_.isObject(value)) return _.matcher(value); return _.property(value); }; _.iteratee = function(value, context) { return cb(value, context, Infinity); }; // An internal function for creating assigner functions. var createAssigner = function(keysFunc, undefinedOnly) { return function(obj) { var length = arguments.length; if (length < 2 || obj == null) return obj; for (var index = 1; index < length; index++) { var source = arguments[index], keys = keysFunc(source), l = keys.length; for (var i = 0; i < l; i++) { var key = keys[i]; if (!undefinedOnly || obj[key] === void 0) obj[key] = source[key]; } } return obj; }; }; // An internal function for creating a new object that inherits from another. var baseCreate = function(prototype) { if (!_.isObject(prototype)) return {}; if (nativeCreate) return nativeCreate(prototype); Ctor.prototype = prototype; var result = new Ctor; Ctor.prototype = null; return result; }; var property = function(key) { return function(obj) { return obj == null ? void 0 : obj[key]; }; }; // Helper for collection methods to determine whether a collection // should be iterated as an array or as an object // Related: http://people.mozilla.org/~jorendorff/es6-draft.html#sec-tolength // Avoids a very nasty iOS 8 JIT bug on ARM-64. #2094 var MAX_ARRAY_INDEX = Math.pow(2, 53) - 1; var getLength = property('length'); var isArrayLike = function(collection) { var length = getLength(collection); return typeof length == 'number' && length >= 0 && length <= MAX_ARRAY_INDEX; }; // Collection Functions // -------------------- // The cornerstone, an `each` implementation, aka `forEach`. // Handles raw objects in addition to array-likes. Treats all // sparse array-likes as if they were dense. _.each = _.forEach = function(obj, iteratee, context) { iteratee = optimizeCb(iteratee, context); var i, length; if (isArrayLike(obj)) { for (i = 0, length = obj.length; i < length; i++) { iteratee(obj[i], i, obj); } } else { var keys = _.keys(obj); for (i = 0, length = keys.length; i < length; i++) { iteratee(obj[keys[i]], keys[i], obj); } } return obj; }; // Return the results of applying the iteratee to each element. _.map = _.collect = function(obj, iteratee, context) { iteratee = cb(iteratee, context); var keys = !isArrayLike(obj) && _.keys(obj), length = (keys || obj).length, results = Array(length); for (var index = 0; index < length; index++) { var currentKey = keys ? keys[index] : index; results[index] = iteratee(obj[currentKey], currentKey, obj); } return results; }; // Create a reducing function iterating left or right. function createReduce(dir) { // Optimized iterator function as using arguments.length // in the main function will deoptimize the, see #1991. function iterator(obj, iteratee, memo, keys, index, length) { for (; index >= 0 && index < length; index += dir) { var currentKey = keys ? keys[index] : index; memo = iteratee(memo, obj[currentKey], currentKey, obj); } return memo; } return function(obj, iteratee, memo, context) { iteratee = optimizeCb(iteratee, context, 4); var keys = !isArrayLike(obj) && _.keys(obj), length = (keys || obj).length, index = dir > 0 ? 0 : length - 1; // Determine the initial value if none is provided. if (arguments.length < 3) { memo = obj[keys ? keys[index] : index]; index += dir; } return iterator(obj, iteratee, memo, keys, index, length); }; } // **Reduce** builds up a single result from a list of values, aka `inject`, // or `foldl`. _.reduce = _.foldl = _.inject = createReduce(1); // The right-associative version of reduce, also known as `foldr`. _.reduceRight = _.foldr = createReduce(-1); // Return the first value which passes a truth test. Aliased as `detect`. _.find = _.detect = function(obj, predicate, context) { var key; if (isArrayLike(obj)) { key = _.findIndex(obj, predicate, context); } else { key = _.findKey(obj, predicate, context); } if (key !== void 0 && key !== -1) return obj[key]; }; // Return all the elements that pass a truth test. // Aliased as `select`. _.filter = _.select = function(obj, predicate, context) { var results = []; predicate = cb(predicate, context); _.each(obj, function(value, index, list) { if (predicate(value, index, list)) results.push(value); }); return results; }; // Return all the elements for which a truth test fails. _.reject = function(obj, predicate, context) { return _.filter(obj, _.negate(cb(predicate)), context); }; // Determine whether all of the elements match a truth test. // Aliased as `all`. _.every = _.all = function(obj, predicate, context) { predicate = cb(predicate, context); var keys = !isArrayLike(obj) && _.keys(obj), length = (keys || obj).length; for (var index = 0; index < length; index++) { var currentKey = keys ? keys[index] : index; if (!predicate(obj[currentKey], currentKey, obj)) return false; } return true; }; // Determine if at least one element in the object matches a truth test. // Aliased as `any`. _.some = _.any = function(obj, predicate, context) { predicate = cb(predicate, context); var keys = !isArrayLike(obj) && _.keys(obj), length = (keys || obj).length; for (var index = 0; index < length; index++) { var currentKey = keys ? keys[index] : index; if (predicate(obj[currentKey], currentKey, obj)) return true; } return false; }; // Determine if the array or object contains a given item (using `===`). // Aliased as `includes` and `include`. _.contains = _.includes = _.include = function(obj, item, fromIndex, guard) { if (!isArrayLike(obj)) obj = _.values(obj); if (typeof fromIndex != 'number' || guard) fromIndex = 0; return _.indexOf(obj, item, fromIndex) >= 0; }; // Invoke a method (with arguments) on every item in a collection. _.invoke = function(obj, method) { var args = slice.call(arguments, 2); var isFunc = _.isFunction(method); return _.map(obj, function(value) { var func = isFunc ? method : value[method]; return func == null ? func : func.apply(value, args); }); }; // Convenience version of a common use case of `map`: fetching a property. _.pluck = function(obj, key) { return _.map(obj, _.property(key)); }; // Convenience version of a common use case of `filter`: selecting only objects // containing specific `key:value` pairs. _.where = function(obj, attrs) { return _.filter(obj, _.matcher(attrs)); }; // Convenience version of a common use case of `find`: getting the first object // containing specific `key:value` pairs. _.findWhere = function(obj, attrs) { return _.find(obj, _.matcher(attrs)); }; // Return the maximum element (or element-based computation). _.max = function(obj, iteratee, context) { var result = -Infinity, lastComputed = -Infinity, value, computed; if (iteratee == null && obj != null) { obj = isArrayLike(obj) ? obj : _.values(obj); for (var i = 0, length = obj.length; i < length; i++) { value = obj[i]; if (value > result) { result = value; } } } else { iteratee = cb(iteratee, context); _.each(obj, function(value, index, list) { computed = iteratee(value, index, list); if (computed > lastComputed || computed === -Infinity && result === -Infinity) { result = value; lastComputed = computed; } }); } return result; }; // Return the minimum element (or element-based computation). _.min = function(obj, iteratee, context) { var result = Infinity, lastComputed = Infinity, value, computed; if (iteratee == null && obj != null) { obj = isArrayLike(obj) ? obj : _.values(obj); for (var i = 0, length = obj.length; i < length; i++) { value = obj[i]; if (value < result) { result = value; } } } else { iteratee = cb(iteratee, context); _.each(obj, function(value, index, list) { computed = iteratee(value, index, list); if (computed < lastComputed || computed === Infinity && result === Infinity) { result = value; lastComputed = computed; } }); } return result; }; // Shuffle a collection, using the modern version of the // [Fisher-Yates shuffle](http://en.wikipedia.org/wiki/Fisher–Yates_shuffle). _.shuffle = function(obj) { var set = isArrayLike(obj) ? obj : _.values(obj); var length = set.length; var shuffled = Array(length); for (var index = 0, rand; index < length; index++) { rand = _.random(0, index); if (rand !== index) shuffled[index] = shuffled[rand]; shuffled[rand] = set[index]; } return shuffled; }; // Sample **n** random values from a collection. // If **n** is not specified, returns a single random element. // The internal `guard` argument allows it to work with `map`. _.sample = function(obj, n, guard) { if (n == null || guard) { if (!isArrayLike(obj)) obj = _.values(obj); return obj[_.random(obj.length - 1)]; } return _.shuffle(obj).slice(0, Math.max(0, n)); }; // Sort the object's values by a criterion produced by an iteratee. _.sortBy = function(obj, iteratee, context) { iteratee = cb(iteratee, context); return _.pluck(_.map(obj, function(value, index, list) { return { value: value, index: index, criteria: iteratee(value, index, list) }; }).sort(function(left, right) { var a = left.criteria; var b = right.criteria; if (a !== b) { if (a > b || a === void 0) return 1; if (a < b || b === void 0) return -1; } return left.index - right.index; }), 'value'); }; // An internal function used for aggregate "group by" operations. var group = function(behavior) { return function(obj, iteratee, context) { var result = {}; iteratee = cb(iteratee, context); _.each(obj, function(value, index) { var key = iteratee(value, index, obj); behavior(result, value, key); }); return result; }; }; // Groups the object's values by a criterion. Pass either a string attribute // to group by, or a function that returns the criterion. _.groupBy = group(function(result, value, key) { if (_.has(result, key)) result[key].push(value); else result[key] = [value]; }); // Indexes the object's values by a criterion, similar to `groupBy`, but for // when you know that your index values will be unique. _.indexBy = group(function(result, value, key) { result[key] = value; }); // Counts instances of an object that group by a certain criterion. Pass // either a string attribute to count by, or a function that returns the // criterion. _.countBy = group(function(result, value, key) { if (_.has(result, key)) result[key]++; else result[key] = 1; }); // Safely create a real, live array from anything iterable. _.toArray = function(obj) { if (!obj) return []; if (_.isArray(obj)) return slice.call(obj); if (isArrayLike(obj)) return _.map(obj, _.identity); return _.values(obj); }; // Return the number of elements in an object. _.size = function(obj) { if (obj == null) return 0; return isArrayLike(obj) ? obj.length : _.keys(obj).length; }; // Split a collection into two arrays: one whose elements all satisfy the given // predicate, and one whose elements all do not satisfy the predicate. _.partition = function(obj, predicate, context) { predicate = cb(predicate, context); var pass = [], fail = []; _.each(obj, function(value, key, obj) { (predicate(value, key, obj) ? pass : fail).push(value); }); return [pass, fail]; }; // Array Functions // --------------- // Get the first element of an array. Passing **n** will return the first N // values in the array. Aliased as `head` and `take`. The **guard** check // allows it to work with `_.map`. _.first = _.head = _.take = function(array, n, guard) { if (array == null) return void 0; if (n == null || guard) return array[0]; return _.initial(array, array.length - n); }; // Returns everything but the last entry of the array. Especially useful on // the arguments object. Passing **n** will return all the values in // the array, excluding the last N. _.initial = function(array, n, guard) { return slice.call(array, 0, Math.max(0, array.length - (n == null || guard ? 1 : n))); }; // Get the last element of an array. Passing **n** will return the last N // values in the array. _.last = function(array, n, guard) { if (array == null) return void 0; if (n == null || guard) return array[array.length - 1]; return _.rest(array, Math.max(0, array.length - n)); }; // Returns everything but the first entry of the array. Aliased as `tail` and `drop`. // Especially useful on the arguments object. Passing an **n** will return // the rest N values in the array. _.rest = _.tail = _.drop = function(array, n, guard) { return slice.call(array, n == null || guard ? 1 : n); }; // Trim out all falsy values from an array. _.compact = function(array) { return _.filter(array, _.identity); }; // Internal implementation of a recursive `flatten` function. var flatten = function(input, shallow, strict, startIndex) { var output = [], idx = 0; for (var i = startIndex || 0, length = getLength(input); i < length; i++) { var value = input[i]; if (isArrayLike(value) && (_.isArray(value) || _.isArguments(value))) { //flatten current level of array or arguments object if (!shallow) value = flatten(value, shallow, strict); var j = 0, len = value.length; output.length += len; while (j < len) { output[idx++] = value[j++]; } } else if (!strict) { output[idx++] = value; } } return output; }; // Flatten out an array, either recursively (by default), or just one level. _.flatten = function(array, shallow) { return flatten(array, shallow, false); }; // Return a version of the array that does not contain the specified value(s). _.without = function(array) { return _.difference(array, slice.call(arguments, 1)); }; // Produce a duplicate-free version of the array. If the array has already // been sorted, you have the option of using a faster algorithm. // Aliased as `unique`. _.uniq = _.unique = function(array, isSorted, iteratee, context) { if (!_.isBoolean(isSorted)) { context = iteratee; iteratee = isSorted; isSorted = false; } if (iteratee != null) iteratee = cb(iteratee, context); var result = []; var seen = []; for (var i = 0, length = getLength(array); i < length; i++) { var value = array[i], computed = iteratee ? iteratee(value, i, array) : value; if (isSorted) { if (!i || seen !== computed) result.push(value); seen = computed; } else if (iteratee) { if (!_.contains(seen, computed)) { seen.push(computed); result.push(value); } } else if (!_.contains(result, value)) { result.push(value); } } return result; }; // Produce an array that contains the union: each distinct element from all of // the passed-in arrays. _.union = function() { return _.uniq(flatten(arguments, true, true)); }; // Produce an array that contains every item shared between all the // passed-in arrays. _.intersection = function(array) { var result = []; var argsLength = arguments.length; for (var i = 0, length = getLength(array); i < length; i++) { var item = array[i]; if (_.contains(result, item)) continue; for (var j = 1; j < argsLength; j++) { if (!_.contains(arguments[j], item)) break; } if (j === argsLength) result.push(item); } return result; }; // Take the difference between one array and a number of other arrays. // Only the elements present in just the first array will remain. _.difference = function(array) { var rest = flatten(arguments, true, true, 1); return _.filter(array, function(value){ return !_.contains(rest, value); }); }; // Zip together multiple lists into a single array -- elements that share // an index go together. _.zip = function() { return _.unzip(arguments); }; // Complement of _.zip. Unzip accepts an array of arrays and groups // each array's elements on shared indices _.unzip = function(array) { var length = array && _.max(array, getLength).length || 0; var result = Array(length); for (var index = 0; index < length; index++) { result[index] = _.pluck(array, index); } return result; }; // Converts lists into objects. Pass either a single array of `[key, value]` // pairs, or two parallel arrays of the same length -- one of keys, and one of // the corresponding values. _.object = function(list, values) { var result = {}; for (var i = 0, length = getLength(list); i < length; i++) { if (values) { result[list[i]] = values[i]; } else { result[list[i][0]] = list[i][1]; } } return result; }; // Generator function to create the findIndex and findLastIndex functions function createPredicateIndexFinder(dir) { return function(array, predicate, context) { predicate = cb(predicate, context); var length = getLength(array); var index = dir > 0 ? 0 : length - 1; for (; index >= 0 && index < length; index += dir) { if (predicate(array[index], index, array)) return index; } return -1; }; } // Returns the first index on an array-like that passes a predicate test _.findIndex = createPredicateIndexFinder(1); _.findLastIndex = createPredicateIndexFinder(-1); // Use a comparator function to figure out the smallest index at which // an object should be inserted so as to maintain order. Uses binary search. _.sortedIndex = function(array, obj, iteratee, context) { iteratee = cb(iteratee, context, 1); var value = iteratee(obj); var low = 0, high = getLength(array); while (low < high) { var mid = Math.floor((low + high) / 2); if (iteratee(array[mid]) < value) low = mid + 1; else high = mid; } return low; }; // Generator function to create the indexOf and lastIndexOf functions function createIndexFinder(dir, predicateFind, sortedIndex) { return function(array, item, idx) { var i = 0, length = getLength(array); if (typeof idx == 'number') { if (dir > 0) { i = idx >= 0 ? idx : Math.max(idx + length, i); } else { length = idx >= 0 ? Math.min(idx + 1, length) : idx + length + 1; } } else if (sortedIndex && idx && length) { idx = sortedIndex(array, item); return array[idx] === item ? idx : -1; } if (item !== item) { idx = predicateFind(slice.call(array, i, length), _.isNaN); return idx >= 0 ? idx + i : -1; } for (idx = dir > 0 ? i : length - 1; idx >= 0 && idx < length; idx += dir) { if (array[idx] === item) return idx; } return -1; }; } // Return the position of the first occurrence of an item in an array, // or -1 if the item is not included in the array. // If the array is large and already in sort order, pass `true` // for **isSorted** to use binary search. _.indexOf = createIndexFinder(1, _.findIndex, _.sortedIndex); _.lastIndexOf = createIndexFinder(-1, _.findLastIndex); // Generate an integer Array containing an arithmetic progression. A port of // the native Python `range()` function. See // [the Python documentation](http://docs.python.org/library/functions.html#range). _.range = function(start, stop, step) { if (stop == null) { stop = start || 0; start = 0; } step = step || 1; var length = Math.max(Math.ceil((stop - start) / step), 0); var range = Array(length); for (var idx = 0; idx < length; idx++, start += step) { range[idx] = start; } return range; }; // Function (ahem) Functions // ------------------ // Determines whether to execute a function as a constructor // or a normal function with the provided arguments var executeBound = function(sourceFunc, boundFunc, context, callingContext, args) { if (!(callingContext instanceof boundFunc)) return sourceFunc.apply(context, args); var self = baseCreate(sourceFunc.prototype); var result = sourceFunc.apply(self, args); if (_.isObject(result)) return result; return self; }; // Create a function bound to a given object (assigning `this`, and arguments, // optionally). Delegates to **ECMAScript 5**'s native `Function.bind` if // available. _.bind = function(func, context) { if (nativeBind && func.bind === nativeBind) return nativeBind.apply(func, slice.call(arguments, 1)); if (!_.isFunction(func)) throw new TypeError('Bind must be called on a function'); var args = slice.call(arguments, 2); var bound = function() { return executeBound(func, bound, context, this, args.concat(slice.call(arguments))); }; return bound; }; // Partially apply a function by creating a version that has had some of its // arguments pre-filled, without changing its dynamic `this` context. _ acts // as a placeholder, allowing any combination of arguments to be pre-filled. _.partial = function(func) { var boundArgs = slice.call(arguments, 1); var bound = function() { var position = 0, length = boundArgs.length; var args = Array(length); for (var i = 0; i < length; i++) { args[i] = boundArgs[i] === _ ? arguments[position++] : boundArgs[i]; } while (position < arguments.length) args.push(arguments[position++]); return executeBound(func, bound, this, this, args); }; return bound; }; // Bind a number of an object's methods to that object. Remaining arguments // are the method names to be bound. Useful for ensuring that all callbacks // defined on an object belong to it. _.bindAll = function(obj) { var i, length = arguments.length, key; if (length <= 1) throw new Error('bindAll must be passed function names'); for (i = 1; i < length; i++) { key = arguments[i]; obj[key] = _.bind(obj[key], obj); } return obj; }; // Memoize an expensive function by storing its results. _.memoize = function(func, hasher) { var memoize = function(key) { var cache = memoize.cache; var address = '' + (hasher ? hasher.apply(this, arguments) : key); if (!_.has(cache, address)) cache[address] = func.apply(this, arguments); return cache[address]; }; memoize.cache = {}; return memoize; }; // Delays a function for the given number of milliseconds, and then calls // it with the arguments supplied. _.delay = function(func, wait) { var args = slice.call(arguments, 2); return setTimeout(function(){ return func.apply(null, args); }, wait); }; // Defers a function, scheduling it to run after the current call stack has // cleared. _.defer = _.partial(_.delay, _, 1); // Returns a function, that, when invoked, will only be triggered at most once // during a given window of time. Normally, the throttled function will run // as much as it can, without ever going more than once per `wait` duration; // but if you'd like to disable the execution on the leading edge, pass // `{leading: false}`. To disable execution on the trailing edge, ditto. _.throttle = function(func, wait, options) { var context, args, result; var timeout = null; var previous = 0; if (!options) options = {}; var later = function() { previous = options.leading === false ? 0 : _.now(); timeout = null; result = func.apply(context, args); if (!timeout) context = args = null; }; return function() { var now = _.now(); if (!previous && options.leading === false) previous = now; var remaining = wait - (now - previous); context = this; args = arguments; if (remaining <= 0 || remaining > wait) { if (timeout) { clearTimeout(timeout); timeout = null; } previous = now; result = func.apply(context, args); if (!timeout) context = args = null; } else if (!timeout && options.trailing !== false) { timeout = setTimeout(later, remaining); } return result; }; }; // Returns a function, that, as long as it continues to be invoked, will not // be triggered. The function will be called after it stops being called for // N milliseconds. If `immediate` is passed, trigger the function on the // leading edge, instead of the trailing. _.debounce = function(func, wait, immediate) { var timeout, args, context, timestamp, result; var later = function() { var last = _.now() - timestamp; if (last < wait && last >= 0) { timeout = setTimeout(later, wait - last); } else { timeout = null; if (!immediate) { result = func.apply(context, args); if (!timeout) context = args = null; } } }; return function() { context = this; args = arguments; timestamp = _.now(); var callNow = immediate && !timeout; if (!timeout) timeout = setTimeout(later, wait); if (callNow) { result = func.apply(context, args); context = args = null; } return result; }; }; // Returns the first function passed as an argument to the second, // allowing you to adjust arguments, run code before and after, and // conditionally execute the original function. _.wrap = function(func, wrapper) { return _.partial(wrapper, func); }; // Returns a negated version of the passed-in predicate. _.negate = function(predicate) { return function() { return !predicate.apply(this, arguments); }; }; // Returns a function that is the composition of a list of functions, each // consuming the return value of the function that follows. _.compose = function() { var args = arguments; var start = args.length - 1; return function() { var i = start; var result = args[start].apply(this, arguments); while (i--) result = args[i].call(this, result); return result; }; }; // Returns a function that will only be executed on and after the Nth call. _.after = function(times, func) { return function() { if (--times < 1) { return func.apply(this, arguments); } }; }; // Returns a function that will only be executed up to (but not including) the Nth call. _.before = function(times, func) { var memo; return function() { if (--times > 0) { memo = func.apply(this, arguments); } if (times <= 1) func = null; return memo; }; }; // Returns a function that will be executed at most one time, no matter how // often you call it. Useful for lazy initialization. _.once = _.partial(_.before, 2); // Object Functions // ---------------- // Keys in IE < 9 that won't be iterated by `for key in ...` and thus missed. var hasEnumBug = !{toString: null}.propertyIsEnumerable('toString'); var nonEnumerableProps = ['valueOf', 'isPrototypeOf', 'toString', 'propertyIsEnumerable', 'hasOwnProperty', 'toLocaleString']; function collectNonEnumProps(obj, keys) { var nonEnumIdx = nonEnumerableProps.length; var constructor = obj.constructor; var proto = (_.isFunction(constructor) && constructor.prototype) || ObjProto; // Constructor is a special case. var prop = 'constructor'; if (_.has(obj, prop) && !_.contains(keys, prop)) keys.push(prop); while (nonEnumIdx--) { prop = nonEnumerableProps[nonEnumIdx]; if (prop in obj && obj[prop] !== proto[prop] && !_.contains(keys, prop)) { keys.push(prop); } } } // Retrieve the names of an object's own properties. // Delegates to **ECMAScript 5**'s native `Object.keys` _.keys = function(obj) { if (!_.isObject(obj)) return []; if (nativeKeys) return nativeKeys(obj); var keys = []; for (var key in obj) if (_.has(obj, key)) keys.push(key); // Ahem, IE < 9. if (hasEnumBug) collectNonEnumProps(obj, keys); return keys; }; // Retrieve all the property names of an object. _.allKeys = function(obj) { if (!_.isObject(obj)) return []; var keys = []; for (var key in obj) keys.push(key); // Ahem, IE < 9. if (hasEnumBug) collectNonEnumProps(obj, keys); return keys; }; // Retrieve the values of an object's properties. _.values = function(obj) { var keys = _.keys(obj); var length = keys.length; var values = Array(length); for (var i = 0; i < length; i++) { values[i] = obj[keys[i]]; } return values; }; // Returns the results of applying the iteratee to each element of the object // In contrast to _.map it returns an object _.mapObject = function(obj, iteratee, context) { iteratee = cb(iteratee, context); var keys = _.keys(obj), length = keys.length, results = {}, currentKey; for (var index = 0; index < length; index++) { currentKey = keys[index]; results[currentKey] = iteratee(obj[currentKey], currentKey, obj); } return results; }; // Convert an object into a list of `[key, value]` pairs. _.pairs = function(obj) { var keys = _.keys(obj); var length = keys.length; var pairs = Array(length); for (var i = 0; i < length; i++) { pairs[i] = [keys[i], obj[keys[i]]]; } return pairs; }; // Invert the keys and values of an object. The values must be serializable. _.invert = function(obj) { var result = {}; var keys = _.keys(obj); for (var i = 0, length = keys.length; i < length; i++) { result[obj[keys[i]]] = keys[i]; } return result; }; // Return a sorted list of the function names available on the object. // Aliased as `methods` _.functions = _.methods = function(obj) { var names = []; for (var key in obj) { if (_.isFunction(obj[key])) names.push(key); } return names.sort(); }; // Extend a given object with all the properties in passed-in object(s). _.extend = createAssigner(_.allKeys); // Assigns a given object with all the own properties in the passed-in object(s) // (https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object/assign) _.extendOwn = _.assign = createAssigner(_.keys); // Returns the first key on an object that passes a predicate test _.findKey = function(obj, predicate, context) { predicate = cb(predicate, context); var keys = _.keys(obj), key; for (var i = 0, length = keys.length; i < length; i++) { key = keys[i]; if (predicate(obj[key], key, obj)) return key; } }; // Return a copy of the object only containing the whitelisted properties. _.pick = function(object, oiteratee, context) { var result = {}, obj = object, iteratee, keys; if (obj == null) return result; if (_.isFunction(oiteratee)) { keys = _.allKeys(obj); iteratee = optimizeCb(oiteratee, context); } else { keys = flatten(arguments, false, false, 1); iteratee = function(value, key, obj) { return key in obj; }; obj = Object(obj); } for (var i = 0, length = keys.length; i < length; i++) { var key = keys[i]; var value = obj[key]; if (iteratee(value, key, obj)) result[key] = value; } return result; }; // Return a copy of the object without the blacklisted properties. _.omit = function(obj, iteratee, context) { if (_.isFunction(iteratee)) { iteratee = _.negate(iteratee); } else { var keys = _.map(flatten(arguments, false, false, 1), String); iteratee = function(value, key) { return !_.contains(keys, key); }; } return _.pick(obj, iteratee, context); }; // Fill in a given object with default properties. _.defaults = createAssigner(_.allKeys, true); // Creates an object that inherits from the given prototype object. // If additional properties are provided then they will be added to the // created object. _.create = function(prototype, props) { var result = baseCreate(prototype); if (props) _.extendOwn(result, props); return result; }; // Create a (shallow-cloned) duplicate of an object. _.clone = function(obj) { if (!_.isObject(obj)) return obj; return _.isArray(obj) ? obj.slice() : _.extend({}, obj); }; // Invokes interceptor with the obj, and then returns obj. // The primary purpose of this method is to "tap into" a method chain, in // order to perform operations on intermediate results within the chain. _.tap = function(obj, interceptor) { interceptor(obj); return obj; }; // Returns whether an object has a given set of `key:value` pairs. _.isMatch = function(object, attrs) { var keys = _.keys(attrs), length = keys.length; if (object == null) return !length; var obj = Object(object); for (var i = 0; i < length; i++) { var key = keys[i]; if (attrs[key] !== obj[key] || !(key in obj)) return false; } return true; }; // Internal recursive comparison function for `isEqual`. var eq = function(a, b, aStack, bStack) { // Identical objects are equal. `0 === -0`, but they aren't identical. // See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal). if (a === b) return a !== 0 || 1 / a === 1 / b; // A strict comparison is necessary because `null == undefined`. if (a == null || b == null) return a === b; // Unwrap any wrapped objects. if (a instanceof _) a = a._wrapped; if (b instanceof _) b = b._wrapped; // Compare `[[Class]]` names. var className = toString.call(a); if (className !== toString.call(b)) return false; switch (className) { // Strings, numbers, regular expressions, dates, and booleans are compared by value. case '[object RegExp]': // RegExps are coerced to strings for comparison (Note: '' + /a/i === '/a/i') case '[object String]': // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is // equivalent to `new String("5")`. return '' + a === '' + b; case '[object Number]': // `NaN`s are equivalent, but non-reflexive. // Object(NaN) is equivalent to NaN if (+a !== +a) return +b !== +b; // An `egal` comparison is performed for other numeric values. return +a === 0 ? 1 / +a === 1 / b : +a === +b; case '[object Date]': case '[object Boolean]': // Coerce dates and booleans to numeric primitive values. Dates are compared by their // millisecond representations. Note that invalid dates with millisecond representations // of `NaN` are not equivalent. return +a === +b; } var areArrays = className === '[object Array]'; if (!areArrays) { if (typeof a != 'object' || typeof b != 'object') return false; // Objects with different constructors are not equivalent, but `Object`s or `Array`s // from different frames are. var aCtor = a.constructor, bCtor = b.constructor; if (aCtor !== bCtor && !(_.isFunction(aCtor) && aCtor instanceof aCtor && _.isFunction(bCtor) && bCtor instanceof bCtor) && ('constructor' in a && 'constructor' in b)) { return false; } } // Assume equality for cyclic structures. The algorithm for detecting cyclic // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`. // Initializing stack of traversed objects. // It's done here since we only need them for objects and arrays comparison. aStack = aStack || []; bStack = bStack || []; var length = aStack.length; while (length--) { // Linear search. Performance is inversely proportional to the number of // unique nested structures. if (aStack[length] === a) return bStack[length] === b; } // Add the first object to the stack of traversed objects. aStack.push(a); bStack.push(b); // Recursively compare objects and arrays. if (areArrays) { // Compare array lengths to determine if a deep comparison is necessary. length = a.length; if (length !== b.length) return false; // Deep compare the contents, ignoring non-numeric properties. while (length--) { if (!eq(a[length], b[length], aStack, bStack)) return false; } } else { // Deep compare objects. var keys = _.keys(a), key; length = keys.length; // Ensure that both objects contain the same number of properties before comparing deep equality. if (_.keys(b).length !== length) return false; while (length--) { // Deep compare each member key = keys[length]; if (!(_.has(b, key) && eq(a[key], b[key], aStack, bStack))) return false; } } // Remove the first object from the stack of traversed objects. aStack.pop(); bStack.pop(); return true; }; // Perform a deep comparison to check if two objects are equal. _.isEqual = function(a, b) { return eq(a, b); }; // Is a given array, string, or object empty? // An "empty" object has no enumerable own-properties. _.isEmpty = function(obj) { if (obj == null) return true; if (isArrayLike(obj) && (_.isArray(obj) || _.isString(obj) || _.isArguments(obj))) return obj.length === 0; return _.keys(obj).length === 0; }; // Is a given value a DOM element? _.isElement = function(obj) { return !!(obj && obj.nodeType === 1); }; // Is a given value an array? // Delegates to ECMA5's native Array.isArray _.isArray = nativeIsArray || function(obj) { return toString.call(obj) === '[object Array]'; }; // Is a given variable an object? _.isObject = function(obj) { var type = typeof obj; return type === 'function' || type === 'object' && !!obj; }; // Add some isType methods: isArguments, isFunction, isString, isNumber, isDate, isRegExp, isError. _.each(['Arguments', 'Function', 'String', 'Number', 'Date', 'RegExp', 'Error'], function(name) { _['is' + name] = function(obj) { return toString.call(obj) === '[object ' + name + ']'; }; }); // Define a fallback version of the method in browsers (ahem, IE < 9), where // there isn't any inspectable "Arguments" type. if (!_.isArguments(arguments)) { _.isArguments = function(obj) { return _.has(obj, 'callee'); }; } // Optimize `isFunction` if appropriate. Work around some typeof bugs in old v8, // IE 11 (#1621), and in Safari 8 (#1929). if (typeof /./ != 'function' && typeof Int8Array != 'object') { _.isFunction = function(obj) { return typeof obj == 'function' || false; }; } // Is a given object a finite number? _.isFinite = function(obj) { return isFinite(obj) && !isNaN(parseFloat(obj)); }; // Is the given value `NaN`? (NaN is the only number which does not equal itself). _.isNaN = function(obj) { return _.isNumber(obj) && obj !== +obj; }; // Is a given value a boolean? _.isBoolean = function(obj) { return obj === true || obj === false || toString.call(obj) === '[object Boolean]'; }; // Is a given value equal to null? _.isNull = function(obj) { return obj === null; }; // Is a given variable undefined? _.isUndefined = function(obj) { return obj === void 0; }; // Shortcut function for checking if an object has a given property directly // on itself (in other words, not on a prototype). _.has = function(obj, key) { return obj != null && hasOwnProperty.call(obj, key); }; // Utility Functions // ----------------- // Run Underscore.js in *noConflict* mode, returning the `_` variable to its // previous owner. Returns a reference to the Underscore object. _.noConflict = function() { root._ = previousUnderscore; return this; }; // Keep the identity function around for default iteratees. _.identity = function(value) { return value; }; // Predicate-generating functions. Often useful outside of Underscore. _.constant = function(value) { return function() { return value; }; }; _.noop = function(){}; _.property = property; // Generates a function for a given object that returns a given property. _.propertyOf = function(obj) { return obj == null ? function(){} : function(key) { return obj[key]; }; }; // Returns a predicate for checking whether an object has a given set of // `key:value` pairs. _.matcher = _.matches = function(attrs) { attrs = _.extendOwn({}, attrs); return function(obj) { return _.isMatch(obj, attrs); }; }; // Run a function **n** times. _.times = function(n, iteratee, context) { var accum = Array(Math.max(0, n)); iteratee = optimizeCb(iteratee, context, 1); for (var i = 0; i < n; i++) accum[i] = iteratee(i); return accum; }; // Return a random integer between min and max (inclusive). _.random = function(min, max) { if (max == null) { max = min; min = 0; } return min + Math.floor(Math.random() * (max - min + 1)); }; // A (possibly faster) way to get the current timestamp as an integer. _.now = Date.now || function() { return new Date().getTime(); }; // List of HTML entities for escaping. var escapeMap = { '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#x27;', '`': '&#x60;' }; var unescapeMap = _.invert(escapeMap); // Functions for escaping and unescaping strings to/from HTML interpolation. var createEscaper = function(map) { var escaper = function(match) { return map[match]; }; // Regexes for identifying a key that needs to be escaped var source = '(?:' + _.keys(map).join('|') + ')'; var testRegexp = RegExp(source); var replaceRegexp = RegExp(source, 'g'); return function(string) { string = string == null ? '' : '' + string; return testRegexp.test(string) ? string.replace(replaceRegexp, escaper) : string; }; }; _.escape = createEscaper(escapeMap); _.unescape = createEscaper(unescapeMap); // If the value of the named `property` is a function then invoke it with the // `object` as context; otherwise, return it. _.result = function(object, property, fallback) { var value = object == null ? void 0 : object[property]; if (value === void 0) { value = fallback; } return _.isFunction(value) ? value.call(object) : value; }; // Generate a unique integer id (unique within the entire client session). // Useful for temporary DOM ids. var idCounter = 0; _.uniqueId = function(prefix) { var id = ++idCounter + ''; return prefix ? prefix + id : id; }; // By default, Underscore uses ERB-style template delimiters, change the // following template settings to use alternative delimiters. _.templateSettings = { evaluate : /<%([\s\S]+?)%>/g, interpolate : /<%=([\s\S]+?)%>/g, escape : /<%-([\s\S]+?)%>/g }; // When customizing `templateSettings`, if you don't want to define an // interpolation, evaluation or escaping regex, we need one that is // guaranteed not to match. var noMatch = /(.)^/; // Certain characters need to be escaped so that they can be put into a // string literal. var escapes = { "'": "'", '\\': '\\', '\r': 'r', '\n': 'n', '\u2028': 'u2028', '\u2029': 'u2029' }; var escaper = /\\|'|\r|\n|\u2028|\u2029/g; var escapeChar = function(match) { return '\\' + escapes[match]; }; // JavaScript micro-templating, similar to John Resig's implementation. // Underscore templating handles arbitrary delimiters, preserves whitespace, // and correctly escapes quotes within interpolated code. // NB: `oldSettings` only exists for backwards compatibility. _.template = function(text, settings, oldSettings) { if (!settings && oldSettings) settings = oldSettings; settings = _.defaults({}, settings, _.templateSettings); // Combine delimiters into one regular expression via alternation. var matcher = RegExp([ (settings.escape || noMatch).source, (settings.interpolate || noMatch).source, (settings.evaluate || noMatch).source ].join('|') + '|$', 'g'); // Compile the template source, escaping string literals appropriately. var index = 0; var source = "__p+='"; text.replace(matcher, function(match, escape, interpolate, evaluate, offset) { source += text.slice(index, offset).replace(escaper, escapeChar); index = offset + match.length; if (escape) { source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'"; } else if (interpolate) { source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'"; } else if (evaluate) { source += "';\n" + evaluate + "\n__p+='"; } // Adobe VMs need the match returned to produce the correct offest. return match; }); source += "';\n"; // If a variable is not specified, place data values in local scope. if (!settings.variable) source = 'with(obj||{}){\n' + source + '}\n'; source = "var __t,__p='',__j=Array.prototype.join," + "print=function(){__p+=__j.call(arguments,'');};\n" + source + 'return __p;\n'; try { var render = new Function(settings.variable || 'obj', '_', source); } catch (e) { e.source = source; throw e; } var template = function(data) { return render.call(this, data, _); }; // Provide the compiled source as a convenience for precompilation. var argument = settings.variable || 'obj'; template.source = 'function(' + argument + '){\n' + source + '}'; return template; }; // Add a "chain" function. Start chaining a wrapped Underscore object. _.chain = function(obj) { var instance = _(obj); instance._chain = true; return instance; }; // OOP // --------------- // If Underscore is called as a function, it returns a wrapped object that // can be used OO-style. This wrapper holds altered versions of all the // underscore functions. Wrapped objects may be chained. // Helper function to continue chaining intermediate results. var result = function(instance, obj) { return instance._chain ? _(obj).chain() : obj; }; // Add your own custom functions to the Underscore object. _.mixin = function(obj) { _.each(_.functions(obj), function(name) { var func = _[name] = obj[name]; _.prototype[name] = function() { var args = [this._wrapped]; push.apply(args, arguments); return result(this, func.apply(_, args)); }; }); }; // Add all of the Underscore functions to the wrapper object. _.mixin(_); // Add all mutator Array functions to the wrapper. _.each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) { var method = ArrayProto[name]; _.prototype[name] = function() { var obj = this._wrapped; method.apply(obj, arguments); if ((name === 'shift' || name === 'splice') && obj.length === 0) delete obj[0]; return result(this, obj); }; }); // Add all accessor Array functions to the wrapper. _.each(['concat', 'join', 'slice'], function(name) { var method = ArrayProto[name]; _.prototype[name] = function() { return result(this, method.apply(this._wrapped, arguments)); }; }); // Extracts the result from a wrapped and chained object. _.prototype.value = function() { return this._wrapped; }; // Provide unwrapping proxy for some methods used in engine operations // such as arithmetic and JSON stringification. _.prototype.valueOf = _.prototype.toJSON = _.prototype.value; _.prototype.toString = function() { return '' + this._wrapped; }; // AMD registration happens at the end for compatibility with AMD loaders // that may not enforce next-turn semantics on modules. Even though general // practice for AMD registration is to be anonymous, underscore registers // as a named module because, like jQuery, it is a base library that is // popular enough to be bundled in a third party lib, but not be part of // an AMD load request. Those cases could generate an error when an // anonymous define() is called outside of a loader request. if (typeof define === 'function' && define.amd) { define('underscore', [], function() { return _; }); } }.call(this));

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