Can i do Expression to keyframes and smooth via script?

hi guys, who know AE scripts can translate expression to linear keyframes via script(now i use app.executeCommand(app.findMenuCommandId("Convert Expression to Keyframes")) ; command) but , for Comman work i must select every time property of layer(opacity, position, scale, etc) where i have expression.... but i need translate very many layers, i always click on property with expression and then do Convert Expression to Keyframes its to long.., can i do something like this

for (var j= 0; j<selectedLayers.length; j++) 

                   {                 

                   var SelLaye= selectedLayers;                  

                   if (SelLayer.transform.opacity.expression!=null && (SelLayer.transform.opacity.expression!=null) && (SelLayer.transform.opacity.expression!=null)) //check if layer have expression

                         {

                         SelLayer.transform.position.select=true;  //and here i need set cursor to position, expression, etc, where i have expression and translate to linear kayframes(but i dont know how)

                         app.executeCommand(app.findMenuCommandId("Convert Expression to Keyframes")) //do translation

                         SelLayer.transform.rotation.select=true;

                         app.executeCommand(app.findMenuCommandId("Convert Expression to Keyframes")) 

                         SelLayer.transform.scale.select=true;

                         app.executeCommand(app.findMenuCommandId("Convert Expression to Keyframes"))

                         //and after this also need do a smoother or something like this for decreasing linear keys for max(because app.executeCommand(app.findMenuCommandId("Convert Expression to Keyframes")) create to many keyframes)

                   }

sorry for bad English