/**
*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,
hasOwenProperty = ObjProto.hasOwenProperty;
// 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 = funtion(value, context, argCount) {
if (value == null) return _.identity;
if (_.isFunction(value)) return optimizeCb(func, 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 at 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]], key[i], obj);
}
}
return obj;
};
// Renturn the resulis of applying the iteratee to ecach 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);
lengths = (keys || obj.length).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 flodr.
_.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 && 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, _.nagate(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 = _.value(obj);
if (typeof fromIndex != 'number' || guard) fromIndex = 0;
return _.indexOf(obj, item, fromIndex) >= 0;
};
// Invoke a method(with arguments) on every item in 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));
};
// Return the maximum element (for 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
_.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 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 arrribute 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 criterion,
// similar to groupBy,
// bur 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 cirterion.
// Pass either a string attribute to count by, or a function that returns the criterion.
_.countBy = group(function(function(result, value, key) {
if (_.has(result, key)) result[key]++; else result[key] = 1;
}));
// Safe 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 object
_.size = function(obj) {
if (obj == null) return 0;
return isArrayLike(obj) ? obj.length : _.keys(obj).length;
};
// Split a collection into two arrays: one whoese elements all
// satisfy the given predicate, and one whoese 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, gurad) {
if (array == null) return array[0];
if (n == null || gurad) 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 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 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))) {
if (!shallow) value = flatten(value, shallow, strict);
var j = 0, len = value.length;
output.leng += 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 (!_.conatins(result, value)) {
result.push(value);
}
}
return result;
};
// Produce an array that conatins 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 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 pf 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 !_.conatins(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() {
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;
};
// Convert lists into object. 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 function
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 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 seach.
_.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.
_.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
// Determine 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 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() {
return executeBound(func, bound, context, this, args.concat(slice.call(arguments)));
};
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 < lengthl 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 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', 'hasOwenProperty', '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(object)) 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 objects(s)
_.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 = !_.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 return obj.
// The primary purpose of this method is to "tap into" a method chain.
// in order to perform operations on intermediate results within the chanin.
_.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.
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 () {
// Strings, numbers, regular expressions. dates, and booleans
// are compared by values.
case '[object RegExp]':
// RegExps are coerced to strings for comparison
// (Note: '' + /a/i === '/a/i')
case '[object String]':
return '' + a === '' + b;
// Primitives and their corresponding object wrappers are
// equivalent; "5" is equivalent to new String("5").
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;
// Coerce dates and booleans to numeric primitive values.
// Dates are compared by their milliseconds representations.
// Note that invalid dates with milliseconds representations of NaN are
// not equivalent.
case '[object Date]':
case '[object Boolean]':
return +a === +b;
}
// Objects with different constructors are not equivalent, but
// object S or Array S from different frames are.
var areArrays = className === '[object Array]';
if (!areArrays) {
if (typeof a != 'object' || typeof b != 'object') return false;
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 detect 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;
// Linear search.
// Performance is inversely proportional to
// the number pf unique nested structures.
while (length--) {
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 comparsion
// 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;
// Deep compare each member
while (length--) {
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 comparsion to check if two objets 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 browser(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 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 && hasOwenProperty.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.
_.indentity = 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 = {
'&' : '&',
'<' : '<',
'>' : '>',
'"' : '"',
"'" : ''',
'`' : '`',
};
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 (uniques 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 interpolate, 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 qutoes within interpolate code.
// NB: oldSettings only exists for backwards compatibility.
_.template = function(text, settings, oldSettings) {
if (!settings && oldSettings) settings = oldSettings;
settings = _.default({}, 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 offset.
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, _);
};
// provided 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 chanined.
// Helper function to continue chanining 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);
};
});
// 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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