Cache in JavaScript

<! DOCTYPE html>//Requirements:        //to implement a function to create a cache: Createcache ()        //1 reading the cache        //2 Adding a cache        //3 Modifying the cache        //4 The number of caches to be controlled within a certain range        //5 each call to create a cached function creates a cache .        //and multiple caches do not affect each other!         //Configuration properties or configuration files        varCachelength = 3; //Analysis:        functionCreatecache () {varCache = {}; //function: Used to record the order of keys stored in the cache            varKeyarr = []; //role: To increase and revise the cache to check            return function(key, value) {//1 Number of parameters to be processed first                //if it is a parameter: indicates a read                //if it is two parameters: indicates a setting                //A. Value = = undefined                //B. Arguments.length                if(Value = = =undefined) {                    returnCache[key]; }                //The following code handles setting up the cache                //1 Modifications                //2 Add                //Cache[key] = = = Undefined                //If the judgment is: true, the description is added                //Otherwise, it is modified                if(Cache[key]!==undefined) {Cache[key]=value; } Else {                    //The following code handles the added logic                    //1 The length of the cache exceeds the limit                    //2 The length of the cache does not exceed the limit                    //arr.length >                    //                         //If you first add data to the data, you can judge the value of the:> limit.                    //if it is the data that is added after judgment, it is: The value of >= limitKeyarr.push (key); if(Keyarr.length >cachelength) {                        //Delete, question: Which piece of data to delete                        //Delete: The data that was first added in the array                        //That is: The value of index number: 0                        varDeleteKey =Keyarr.shift (); DeleteCache[deletekey]; }                    //add data to the cache regardless of whether the data is deleted or not deletedCache[key] =value;        }            }; }        //lvha = LV Hao        //: Linked        //: Visited        //: Hover        //: Active        //called        varTypecache =Createcache (); //To Add a cache:Typecache ("Class", ". CLS"); Typecache ("id", "#dv"); Typecache ("Tag", "Div, P"); Typecache ("Tag", "Span"); Typecache (": Even", "dddd"); //read:Console.log (Typecache ("class"));//. CLSConsole.log (Typecache ("id"));//#dvConsole.log (Typecache ("tag"));//spanConsole.log (Typecache (": even"));//span        varStrcache =Createcache (); </script> <script type= "Text/javascript" >varCachelength = 3; //Optimized Code        functionCreatecache () {//function: Used to record the order of keys stored in the cache            varCache = {},            //role: To increase and revise the cache to checkKeyarr = []; return function(key, value) {if(Value = = =undefined) {                    returnCache[key]; }                if(Cache[key] = = =undefined) {                    //return value of the Push method: length after adding data                    if(Keyarr.push (key) >cachelength) {                        Deletecache[Keyarr.shift ()]; }} Cache[key]=value;        }; }        //called        varTypecache =Createcache (); //To Add a cache:Typecache ("Class", ". CLS"); Typecache ("id", "#dv"); Typecache ("Tag", "Div, P"); Typecache ("Tag", "Span"); Typecache (": Even", "dddd"); //read:Console.log (Typecache ("class"));//undefinedConsole.log (Typecache ("id"));//#dvConsole.log (Typecache ("tag"));//spanConsole.log (Typecache (": even"));//dddd</script></body>
Cache in JavaScript