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Name

sn_devstudio._
Description

underscore library
Script

//     Underscore.js 1.8.2
//     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 = '1.8.2';

// 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;
};

// 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
var MAX_ARRAY_INDEX = Math.pow(2, 53) - 1;
var isArrayLike = function(collection) {
  var length = collection && collection.length;
  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 value (using `===`).
// Aliased as `includes` and `include`.
_.contains = _.includes = _.include = function(obj, target, fromIndex) {
  if (!isArrayLike(obj)) obj = _.values(obj);
  return _.indexOf(obj, target, typeof fromIndex == 'number' && 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 = input && input.length; 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 (array == null) return [];
  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 = array.length; 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) {
  if (array == null) return [];
  var result = [];
  var argsLength = arguments.length;
  for (var i = 0, length = array.length; 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, 'length').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 = list && list.length; i < length; i++) {
    if (values) {
      result[list[i]] = values[i];
    } else {
      result[list[i][0]] = list[i][1];
    }
  }
  return result;
};

// 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 = function(array, item, isSorted) {
  var i = 0, length = array && array.length;
  if (typeof isSorted == 'number') {
    i = isSorted < 0 ? Math.max(0, length + isSorted) : isSorted;
  } else if (isSorted && length) {
    i = _.sortedIndex(array, item);
    return array[i] === item ? i : -1;
  }
  if (item !== item) {
    return _.findIndex(slice.call(array, i), _.isNaN);
  }
  for (; i < length; i++) if (array[i] === item) return i;
  return -1;
};

_.lastIndexOf = function(array, item, from) {
  var idx = array ? array.length : 0;
  if (typeof from == 'number') {
    idx = from < 0 ? idx + from + 1 : Math.min(idx, from + 1);
  }
  if (item !== item) {
    return _.findLastIndex(slice.call(array, 0, idx), _.isNaN);
  }
  while (--idx >= 0) if (array[idx] === item) return idx;
  return -1;
};

// Generator function to create the findIndex and findLastIndex functions
function createIndexFinder(dir) {
  return function(array, predicate, context) {
    predicate = cb(predicate, context);
    var length = array != null && array.length;
    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 = createIndexFinder(1);

_.findLastIndex = createIndexFinder(-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 = array.length;
  while (low < high) {
    var mid = Math.floor((low + high) / 2);
    if (iteratee(array[mid]) < value) low = mid + 1; else high = mid;
  }
  return low;
};

// 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 (arguments.length <= 1) {
    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);

// 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 = function(key) {
  return function(obj) {
    return obj == null ? void 0 : obj[key];
  };
};

// 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));
Sys ID

247a4501eb31310007e48c1cf106fed3
Offical Documentation

Official Docs: