RMMV Inserting code into default's game functionality

[HenriqueBG]

var _Scene_Map_onMapLoaded_base = Scene_Map.prototype.onMapLoaded;

Scene_Map.prototype.onMapLoaded = function () {

    _Scene_Map_onMapLoaded_base.call(this);
    //code
}

I have been using this on some plugins where i need to execute after the map is loaded (events created).
I guess i am inserting code between, or before the onMapLoaded..
don't really know..

I would love if someone could explain me exactly what is going on here.

Step by step, like if i was using the debugger (i tryed this), what am i doing here? is this like a middleware?

 

[TheoAllen]

It means you're preserving the previous function in order to preserve the previous code. Then add your own.

var _Scene_Map_onMapLoaded_base = Scene_Map.prototype.onMapLoaded;

This is the code that preserves it.

_Scene_Map_onMapLoaded_base.call(this);

Then call the preserved code so that the original code is executed.

   //code

Then add your own.

 

[HenriqueBG]

Thank you very much. It makes sense now!