Dynamic generation of JavaScript anonymous Functions

An example in the book of the Helper House (www.bkjia.com) is incorrect. Modified it. Below is my understanding! This is what I wrote in the book. I added some annotations:

Reference content is as follows: Function User (props ){ For (var prop in props ){ (Function (currentObj) {// The currentObj here is passed by this. This is User Alert (currentObj. constructor); // You Can See That currentObj is User // Create a new getter (Reader) for this attribute) CurrentObj ["get" + prop] = function (){ // Alert (props. name + "" + props. age + "" + prop ); Return props [prop]; } // Create a new setter for this attribute (setter) CurrentObj ["set" + prop] = function (val ){ Props [prop] = val; }; }) (This); // here this is the User } } Var user = new User ({"name": "chengkai", "age": 22 }); // Note that the name attribute does not exist because it is a private variable of the property object (props Obj ). Alert (user. name = null); // Output true Alert (user. getname (); // output 22 Alert (user. getage (); // output 22

As above: Why is the output 22 like this? Haha. Here is the closure problem !!

Correction:

Reference content is as follows: // **************** Dynamic generation method ******************* *** // Props object, such as: {"name": "chengkai", "age": 22} // Fire station long network, http://www.liehuo.org/ //************************************** ********** Function User (props ){ For (var prop in props ){ (Function (currentObj) {// The currentObj here is passed by this. This is User // Create a new getter (Reader) for this attribute) (Function (prop ){ CurrentObj ["get" + prop] = function (){ // Alert (props. name + "" + props. age + "" + prop ); Return props [prop]; } // Create a new setter for this attribute (setter) CurrentObj ["set" + prop] = function (val ){ Props [prop] = val; }; }) (Prop ); }) (This); // here this is the User } } Var user = new User ({"name": "chengkai", "age": 22 }); // Note that the name attribute does not exist because it is a private variable of the property object (props Obj ). Alert (user. name = null); // Output true Alert (user. getname (); // output chengkai User. setage (11 ); User. setname ("kai "); Alert (user. getage (); // output 11 Alert (user. getname (); // output kai

Pay attention to the differences before and after, and understand the application of the above anonymous function. It should be nice to see what's going on!