The collection class through which JavaScript is implemented

A collection is a data structure that represents an unordered collection of distinct values. The underlying methods of a collection include adding values, detecting whether the values are in the collection, and this collection requires a common implementation to ensure operational efficiency.

A JavaScript object is a basic collection of property names and their corresponding values. A generic set class is implemented with JavaScript, which implements a mapping from JS to a unique string, and then uses the string as the property name. Objects and functions do not have such a concise and reliable unique string representation.

Therefore, the collection class must define a unique property identifier for each object or function in the collection.

1 //Generic collection Classes2 functionSet () {//This is a constructor function3      This. value={};//collection data is stored in the properties of the object4      This. n=0;//the number of values in the collection5      This. add.apply ( This, arguments);//Add all parameters to this collection6 }7 8 //add each parameter to the collection9Set.prototype.add=function(){Ten      for(vari=0;i<arguments.length;i++) {//traverse each parameter One         varVal=arguments[i];//values to add to the collection A         varStr=set._v2s (Val);//convert it to a string -         if(! This. Value.hasownproperty (str)) {//if not in the collection -              This. Value[str]=val;//the string and the value correspond. the              This. n++;//count of values in the collection -         } -     } -     return  This;//support for chained method calls + } -  + //removes an element from the collection, and the delete element is specified by the parameter ASet.prototype.remove=function(){ at      for(vari=0;i<arguments.length;i++){ -         varStr=Set._v2s (Arguments[i]); -         if( This. Values.hasownproperty (str)) { -             Delete  This. Value[str]; -              This. n--; -         } in     } -     return  This; to } +  - //iterates through all the elements in the collection, calling F in the specified context theSet.prototype.foreach=function(f,context) { *      for(varSinch  This. Values) { $         if( This. Value.hasownproperty (s))//Ignore inherited propertiesPanax NotoginsengF.call (Context, This. Value[s]); -     } the } +  A //This is an intrinsic function that corresponds to any JavaScript value and a unique string . theset._v2s=function(val) { +     Switch(val) { -          CaseUndefinedreturn' U '; $          Case NULL:returnN; $          Case true:return' t '; -          Case false:return' F '; -         default:Switch(typeofval) { the              Case' Number ':return' # ' +Val; -              Case' String ':return' "' +Val;Wuyi             default:return' @ ' +ObjectId (val); the         } -     } Wu      -     //for any object, a string will be returned About     //for different objects, this function returns a different string $     //The same string is always returned for multiple calls to the same object -     //to do this, it creates an attribute for O, in ES5, which is not enumerable and is read-only -     functionobjectId (o) { -         varprop= "|**objectid**|";//private attribute for storing ID A         if(!o.hasownproperty (prop))//if the object does not have an ID +o[prop]=set._v2s.next++;//assign the next value to it the         returnO[prop];//return this ID -     } $ }; theset._v2s.next=100;//set Initial ID value

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From the JavaScript authoritative guide 9.6.1

The collection class through which JavaScript is implemented