Javascript to delete last 4 bookmarks of every 10 bookmarks

[Jagdish32850455wqbk]

Hi

I have cobbled up some javascript to delete last 4 bookmarks of every 10 bookmarks but it gives me an error saying "TypeError: bm.children[0].children is null
13:Folder-Level:App:Remove last 4 of every 10 bookmarks.js"

Here is the script

if (app.viewerVersion < 10) {
app.addMenuItem({ cName: "RemBM last4every10", cUser: "RemBM last4every10", cParent: "Tools", 
cExec: "Removelast4ofevery10BM(this)", cEnable: "event.rc = (event.target != null);"}); 
} else {
app.addToolButton({ cName: "RemBM last4every10", cLabel: "RemBM last4every10", cTooltext: "RemBM last4every10", 
cExec: "Removelast4ofevery10BM(this)", cEnable: "event.rc = (event.target != null);"}); 
}
/* Remove last 4 of every 10 BM in the document */
function Removelast4ofevery10BM(doc) {
   console.clear(); console.show();
   var bm = this.bookmarkRoot;
   var bmlength = bm.children[0].children[0].children.length;
   try {
      for (var i = 0; i < bmlength; i++) {
          if (i % 10 >= 6) { // Remove the last 4 bookmarks out of every 10
              bm.children[0].children[0].children[i].remove();
          }
      }
   }
   catch(e) {
   app.alert("Processing error: "+e)
   }
}

Can someone help please. I am a total novice with javascript. It would be greatly appreciated.

[Bernd Alheit]

Has the first bookmark childrens?

[Jagdish32850455wqbk]

No, none of the bookmarks have any children.

[Bernd Alheit]

This explains the error message.

[try67]

Beside the issue with the non-existing children bookmarks you're trying to access, there are several other issues with your code. Try this:

Removelast4ofevery10BM(this);
function Removelast4ofevery10BM(doc) {
   var bm = doc.bookmarkRoot;
   if (bm!=null) {
      for (var i = bm.children.length-1; i>0; i--) {
          if (((i+1)%10)==0) { // Remove the last 4 bookmarks out of every 10
            bm.children[i].remove();
            bm.children[i-1].remove();
            bm.children[i-2].remove();
            bm.children[i-3].remove();
          }
      }
   }
}

[Jagdish32850455wqbk]

Thank you try67. Your code works brilliantly. The code I had created was from chatGPT so it has a very long way to go I guess. Thank you one again.