Set indentation levels and font sizes for nested lists in google doc

set_indentation_and_font_size.js

function onOpen() {
  var ui = DocumentApp.getUi();
  ui.createMenu('Custom Menu')
    .addItem('Set Indentation and Font Size', 'setIndentationAndFontSize')
    .addToUi();
}

function setIndentationAndFontSize() {
  // var doc = DocumentApp.getActiveDocument();
  var doc = DocumentApp.openById('<<<<YOUR-DOCUMENT-ID>>>>');
  var body = doc.getBody();
  Logger.log(body);
  
  // Define indentation amounts and font sizes for each nesting level
  var indentationLevelsStart = [0,25,50,75,100,115]; // Adjust indentation values as needed
  var fontSizes = [18,14,10,8,6,6]; // Adjust font sizes as needed
  
  // Get all paragraphs in the document
  var paragraphs = body.getParagraphs();
  var numberedLists = body.getListItems();

  for (var i =0; i < numberedLists.length; i++) {
    var listItem = numberedLists[i];
    var nestingLevel = Math.floor(listItem.getNestingLevel());
    if (nestingLevel >= 0 && nestingLevel <= 6) {
        // Set the appropriate indentation and font size based on nesting level
        var indentationStart = indentationLevelsStart[nestingLevel];
        var indentationFirst = indentationStart + 18;
        var fontSize = fontSizes[nestingLevel];

        listItem.setIndentFirstLine(indentationStart);  
        try {listItem.setIndentStart(indentationFirst);}     
        catch (error){Logger.log(error);}
        
        listItem.setFontSize(fontSize);
        listItem.setGlyphType(DocumentApp.GlyphType.BULLET).setGlyphType(DocumentApp.GlyphType.NUMBER);
      }
  }
}