JavaScript closures, recursion, deep copy

Closed Package

Understanding:The A function executes and return the b function and the b function can access a The data for the function

Benefit: The child function is stored inside the complex function, and the child function is not automatically destroyed after execution

Cons: Large memory footprint

Ex

function Bibao () {     var i=10;      return function () {         console.log (i);          return i++;}    } var bibao_task=Bibao (); Bibao_task (); Bibao_task (); Bibao_task ();

Recursive

Understanding: Child elements have child elements, child elements have child elements .....

Deep copy and shallow copy

Understanding: The difference between human cloning and shadow, memory address

Deep Copy:

Json Functions

Target=json.parse (json.stringify (obj))

$.extend of Jq

$.extend (true, target,obj)//parameter is true for deep copy, otherwise shallow copy

Recursive deep copy

varChina ={Nation:China, birthplaces:{name:' Chen '      }}//For deep replication, recursion is required to achievevarNewc={};functionCopy (CHINA,NEWC) { for(IinchChina ) {        if(typeofchina[i]=== ' object ') {Newc[i]=China[i]; Copy (China[i],newc[i])}Else{Newc[i]=China[i]}}} Copy (CHINA,NEWC); Console.log (NEWC)

JavaScript closures, recursive, deep copy