JS Implementation Extend function

Write a function, the name of the function is extend, there are two parameters: Destination,source

1. If destination and source are JSON objects, complete the copy from source to destination
2. If destination is a function, source is a JSON object, then each key,value in source is assigned to destination prototype
3, if the Destination,source is a function, then the source of the contents of the prototype is assigned to destination prototype

1 varExtend =function(destination,source) {2     if(typeofDestination = = "Object") {//destination is a JSON object3         if(typeofSource = = "Object") {//source is a JSON object4             //assigns each Key,value value in source to destination5              for(varIinchsource) {6Destination[i] =Source[i];7             }8         }9     }Ten      One     if(typeofDestination = = "function"){ A         if(typeofSource = = "Object"){ -              for(varIinchsource) { -Destination.prototype[i] =Source[i]; the             } -         } -         if(typeofSource = = "function"){ -Destination.prototype =Source.prototype; +         } -     } +     returndestination; A}

JS Implementation Extend function