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							409 lines
						
					
					
						
							7.9 KiB
						
					
					
				| /**
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|  * Mnemonist MultiMap
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|  * ===================
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|  *
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|  * Implementation of a MultiMap with custom container.
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|  */
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| var Iterator = require('obliterator/iterator'),
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|     forEach = require('obliterator/foreach');
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| 
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| /**
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|  * MultiMap.
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|  *
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|  * @constructor
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|  */
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| function MultiMap(Container) {
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| 
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|   this.Container = Container || Array;
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|   this.items = new Map();
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|   this.clear();
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| 
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|   Object.defineProperty(this.items, 'constructor', {
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|     value: MultiMap,
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|     enumerable: false
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|   });
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| }
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| 
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| /**
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|  * Method used to clear the structure.
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|  *
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|  * @return {undefined}
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|  */
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| MultiMap.prototype.clear = function() {
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| 
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|   // Properties
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|   this.size = 0;
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|   this.dimension = 0;
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|   this.items.clear();
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| };
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| 
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| /**
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|  * Method used to set a value.
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|  *
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|  * @param  {any}      key   - Key.
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|  * @param  {any}      value - Value to add.
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|  * @return {MultiMap}
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|  */
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| MultiMap.prototype.set = function(key, value) {
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|   var container = this.items.get(key),
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|       sizeBefore;
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| 
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|   if (!container) {
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|     this.dimension++;
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|     container = new this.Container();
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|     this.items.set(key, container);
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|   }
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| 
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|   if (this.Container === Set) {
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|     sizeBefore = container.size;
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|     container.add(value);
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| 
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|     if (sizeBefore < container.size)
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|       this.size++;
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|   }
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|   else {
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|     container.push(value);
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|     this.size++;
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|   }
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| 
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|   return this;
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| };
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| 
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| /**
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|  * Method used to delete the given key.
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|  *
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|  * @param  {any}     key - Key to delete.
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|  * @return {boolean}
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|  */
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| MultiMap.prototype.delete = function(key) {
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|   var container = this.items.get(key);
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| 
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|   if (!container)
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|     return false;
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| 
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|   this.size -= (this.Container === Set ? container.size : container.length);
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|   this.dimension--;
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|   this.items.delete(key);
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| 
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|   return true;
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| };
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| 
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| /**
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|  * Method used to delete the remove an item in the container stored at the
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|  * given key.
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|  *
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|  * @param  {any}     key - Key to delete.
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|  * @return {boolean}
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|  */
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| MultiMap.prototype.remove = function(key, value) {
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|   var container = this.items.get(key),
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|       wasDeleted,
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|       index;
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| 
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|   if (!container)
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|     return false;
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| 
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|   if (this.Container === Set) {
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|     wasDeleted = container.delete(value);
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| 
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|     if (wasDeleted)
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|       this.size--;
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| 
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|     if (container.size === 0) {
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|       this.items.delete(key);
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|       this.dimension--;
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|     }
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| 
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|     return wasDeleted;
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|   }
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|   else {
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|     index = container.indexOf(value);
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| 
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|     if (index === -1)
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|       return false;
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| 
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|     this.size--;
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| 
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|     if (container.length === 1) {
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|       this.items.delete(key);
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|       this.dimension--;
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| 
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|       return true;
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|     }
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| 
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|     container.splice(index, 1);
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| 
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|     return true;
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|   }
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| };
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| 
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| /**
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|  * Method used to return whether the given keys exists in the map.
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|  *
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|  * @param  {any}     key - Key to check.
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|  * @return {boolean}
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|  */
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| MultiMap.prototype.has = function(key) {
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|   return this.items.has(key);
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| };
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| 
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| /**
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|  * Method used to return the container stored at the given key or `undefined`.
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|  *
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|  * @param  {any}     key - Key to get.
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|  * @return {boolean}
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|  */
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| MultiMap.prototype.get = function(key) {
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|   return this.items.get(key);
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| };
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| 
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| /**
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|  * Method used to return the multiplicity of the given key, meaning the number
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|  * of times it is set, or, more trivially, the size of the attached container.
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|  *
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|  * @param  {any}     key - Key to check.
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|  * @return {number}
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|  */
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| MultiMap.prototype.multiplicity = function(key) {
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|   var container = this.items.get(key);
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| 
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|   if (typeof container === 'undefined')
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|     return 0;
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| 
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|   return this.Container === Set ? container.size : container.length;
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| };
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| MultiMap.prototype.count = MultiMap.prototype.multiplicity;
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| 
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| /**
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|  * Method used to iterate over each of the key/value pairs.
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|  *
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|  * @param  {function}  callback - Function to call for each item.
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|  * @param  {object}    scope    - Optional scope.
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|  * @return {undefined}
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|  */
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| MultiMap.prototype.forEach = function(callback, scope) {
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|   scope = arguments.length > 1 ? scope : this;
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| 
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|   // Inner iteration function is created here to avoid creating it in the loop
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|   var key;
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|   function inner(value) {
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|     callback.call(scope, value, key);
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|   }
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| 
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|   this.items.forEach(function(container, k) {
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|     key = k;
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|     container.forEach(inner);
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|   });
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| };
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| 
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| /**
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|  * Method used to iterate over each of the associations.
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|  *
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|  * @param  {function}  callback - Function to call for each item.
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|  * @param  {object}    scope    - Optional scope.
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|  * @return {undefined}
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|  */
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| MultiMap.prototype.forEachAssociation = function(callback, scope) {
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|   scope = arguments.length > 1 ? scope : this;
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| 
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|   this.items.forEach(callback, scope);
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| };
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| 
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| /**
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|  * Method returning an iterator over the map's keys.
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|  *
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|  * @return {Iterator}
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|  */
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| MultiMap.prototype.keys = function() {
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|   return this.items.keys();
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| };
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| 
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| /**
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|  * Method returning an iterator over the map's keys.
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|  *
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|  * @return {Iterator}
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|  */
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| MultiMap.prototype.values = function() {
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|   var iterator = this.items.values(),
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|       inContainer = false,
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|       countainer,
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|       step,
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|       i,
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|       l;
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| 
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|   if (this.Container === Set)
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|     return new Iterator(function next() {
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|       if (!inContainer) {
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|         step = iterator.next();
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| 
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|         if (step.done)
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|           return {done: true};
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| 
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|         inContainer = true;
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|         countainer = step.value.values();
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|       }
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| 
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|       step = countainer.next();
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| 
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|       if (step.done) {
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|         inContainer = false;
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|         return next();
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|       }
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| 
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|       return {
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|         done: false,
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|         value: step.value
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|       };
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|     });
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| 
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|   return new Iterator(function next() {
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|     if (!inContainer) {
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|       step = iterator.next();
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| 
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|       if (step.done)
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|         return {done: true};
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| 
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|       inContainer = true;
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|       countainer = step.value;
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|       i = 0;
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|       l = countainer.length;
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|     }
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| 
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|     if (i >= l) {
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|       inContainer = false;
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|       return next();
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|     }
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| 
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|     return {
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|       done: false,
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|       value: countainer[i++]
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|     };
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|   });
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| };
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| 
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| /**
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|  * Method returning an iterator over the map's entries.
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|  *
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|  * @return {Iterator}
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|  */
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| MultiMap.prototype.entries = function() {
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|   var iterator = this.items.entries(),
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|       inContainer = false,
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|       countainer,
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|       step,
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|       key,
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|       i,
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|       l;
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| 
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|   if (this.Container === Set)
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|     return new Iterator(function next() {
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|       if (!inContainer) {
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|         step = iterator.next();
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| 
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|         if (step.done)
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|           return {done: true};
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| 
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|         inContainer = true;
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|         key = step.value[0];
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|         countainer = step.value[1].values();
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|       }
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| 
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|       step = countainer.next();
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| 
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|       if (step.done) {
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|         inContainer = false;
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|         return next();
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|       }
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| 
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|       return {
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|         done: false,
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|         value: [key, step.value]
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|       };
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|     });
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| 
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|   return new Iterator(function next() {
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|     if (!inContainer) {
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|       step = iterator.next();
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| 
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|       if (step.done)
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|         return {done: true};
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| 
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|       inContainer = true;
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|       key = step.value[0];
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|       countainer = step.value[1];
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|       i = 0;
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|       l = countainer.length;
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|     }
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| 
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|     if (i >= l) {
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|       inContainer = false;
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|       return next();
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|     }
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| 
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|     return {
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|       done: false,
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|       value: [key, countainer[i++]]
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|     };
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|   });
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| };
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| 
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| /**
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|  * Method returning an iterator over the map's containers.
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|  *
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|  * @return {Iterator}
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|  */
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| MultiMap.prototype.containers = function() {
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|   return this.items.values();
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| };
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| 
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| /**
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|  * Method returning an iterator over the map's associations.
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|  *
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|  * @return {Iterator}
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|  */
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| MultiMap.prototype.associations = function() {
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|   return this.items.entries();
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| };
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| 
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| /**
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|  * Attaching the #.entries method to Symbol.iterator if possible.
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|  */
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| if (typeof Symbol !== 'undefined')
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|   MultiMap.prototype[Symbol.iterator] = MultiMap.prototype.entries;
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| 
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| /**
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|  * Convenience known methods.
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|  */
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| MultiMap.prototype.inspect = function() {
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|   return this.items;
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| };
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| 
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| if (typeof Symbol !== 'undefined')
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|   MultiMap.prototype[Symbol.for('nodejs.util.inspect.custom')] = MultiMap.prototype.inspect;
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| MultiMap.prototype.toJSON = function() {
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|   return this.items;
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| };
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| 
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| /**
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|  * Static @.from function taking an arbitrary iterable & converting it into
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|  * a structure.
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|  *
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|  * @param  {Iterable} iterable  - Target iterable.
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|  * @param  {Class}    Container - Container.
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|  * @return {MultiMap}
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|  */
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| MultiMap.from = function(iterable, Container) {
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|   var map = new MultiMap(Container);
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| 
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|   forEach(iterable, function(value, key) {
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|     map.set(key, value);
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|   });
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| 
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|   return map;
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| };
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| 
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| /**
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|  * Exporting.
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|  */
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| module.exports = MultiMap;
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