javascript - A library with close can't create a new obj base on its constructor -

i received error of uncaught typeerror: object not function on line new can run if var item = mylib;

however, not clear issue here.

(function(window){     function mylib (){         var library={};         library.localvar1="one";         library.localvar2="two";         library.func1 = function (){             console.log("func1 output"+library.localvar1)             return true;         }         library.func2 = function (){             library.func2var1   = "func2one";             console.log("func2 output"+library.localvar2)             return library.func2var1;         }         return library;     }     //define globally if doesn't exist     if(typeof(library) === 'undefined'){         window.mylib = mylib();     }     else{         console.log("library defined.");     }  })(window);  var item =  new window.mylib;     console.log(item.localvar2,"var2");     console.log(item.func2(),"func2");     console.log(item.func1(),"func1"); 

as use var item = new window.mylib; assume want create new instance library.

but in code, library object, not constructor, constructor should function. you'll error.

(function(window){      function mylib (){          var library = function() {            // set self's variable            this.localvar1="one";            this.localvar2="two";          }                    // use prototype define shared function.          library.prototype.func1 =  function (){              console.log("func1 output"+this.localvar1)              return true;          };                  library.prototype.func2 =  function (){              library.func2var1   = "func2one";              console.log("func2 output"+this.localvar2)              return library.func2var1;          };            return library;      }      //define globally if doesn't exist      if(typeof(library) === 'undefined'){          window.mylib = mylib();      }      else{          console.log("library defined.");      }    })(window);    var item =  new window.mylib();  // create instance of library      console.log(item.localvar2,"var2");      console.log(item.func2(),"func2");      console.log(item.func1(),"func1");