italic-yellow-code.gs

function onHomepage(e) {
  return buildHomeCard_();
}

function buildHomeCard_() {
  var card = CardService.newCardBuilder()
    .setHeader(CardService.newCardHeader().setTitle('Italic Highlighter'))
    .addSection(
      CardService.newCardSection()
        .addWidget(CardService.newTextParagraph()
          .setText('Подсветить курсив жёлтым в текущем документе.'))
        .addWidget(
          CardService.newTextButton()
            .setText('Подсветить курсив')
            .setOnClickAction(CardService.newAction().setFunctionName('runHighlight_'))
        )
        .addWidget(
          CardService.newTextButton()
            .setText('Снять подсветку')
            .setOnClickAction(CardService.newAction().setFunctionName('runClear_'))
        )
    )
    .build();
  return card;
}

function runHighlight_(e) {
  var doc = DocumentApp.getActiveDocument();
  if (!doc) throw new Error('Нет активного документа');
  highlightItalicInDocument_(doc);
  return CardService.newActionResponseBuilder()
    .setNotification(CardService.newNotification().setText('Готово: курсив подсвечен'))
    .build();
}

function runClear_(e) {
  var doc = DocumentApp.getActiveDocument();
  if (!doc) throw new Error('Нет активного документа');
  clearItalicBackground_(doc);
  return CardService.newActionResponseBuilder()
    .setNotification(CardService.newNotification().setText('Готово: подсветка снята'))
    .build();
}

/* ===== ЛОГИКА ОБРАБОТКИ ДОКА ===== */

function highlightItalicInDocument_(doc) {
  var body = doc.getBody();
  if (body) {
    var n = body.getNumChildren();
    for (var i = 0; i < n; i++) processElementSafely_(body.getChild(i), true);
  }
  var header = doc.getHeader(); if (header) processElementSafely_(header, true);
  var footer = doc.getFooter(); if (footer) processElementSafely_(footer, true);
}

function clearItalicBackground_(doc) {
  var body = doc.getBody();
  if (body) {
    var n = body.getNumChildren();
    for (var i = 0; i < n; i++) processElementSafely_(body.getChild(i), false);
  }
  var header = doc.getHeader(); if (header) processElementSafely_(header, false);
  var footer = doc.getFooter(); if (footer) processElementSafely_(footer, false);
}

function processElementSafely_(el, doHighlight) {
  try { processElement_(el, doHighlight); } catch (e) { console.log('Skip element: ' + e); }
}

function processElement_(el, doHighlight) {
  var ET = DocumentApp.ElementType;
  var t = el.getType();

  if (t === ET.TEXT) { 
    if (doHighlight) highlightItalicInText_(el.asText());
    else clearItalicInText_(el.asText());
    return; 
  }

  if (t === ET.PARAGRAPH || t === ET.LIST_ITEM) {
    var cnt = el.getNumChildren ? el.getNumChildren() : 0;
    if (cnt > 0) {
      for (var i = 0; i < cnt; i++) processElementSafely_(el.getChild(i), doHighlight);
    } else if (el.editAsText) {
      var txt = el.editAsText();
      if (doHighlight) highlightItalicInText_(txt);
      else clearItalicInText_(txt);
    }
    return;
  }

  if (t === ET.TABLE) {
    var table = el.asTable();
    for (var r = 0; r < table.getNumRows(); r++) {
      var row = table.getRow(r);
      for (var c = 0; c < row.getNumCells(); c++) {
        var cell = row.getCell(c);
        for (var k = 0; k < cell.getNumChildren(); k++) {
          processElementSafely_(cell.getChild(k), doHighlight);
        }
      }
    }
    return;
  }

  if (el.getNumChildren) {
    for (var j = 0; j < el.getNumChildren(); j++) {
      processElementSafely_(el.getChild(j), doHighlight);
    }
  }
}

/* ===== Работа с текстом (устойчиво по индексам) ===== */

function highlightItalicInText_(textElement) {
  if (!textElement) return;
  var text = textElement.getText(); if (!text) return;
  var len = text.length; if (len === 0) return;

  var indices = textElement.getTextAttributeIndices();
  for (var i = 0; i < indices.length; i++) {
    var start = indices[i];
    var end = (i + 1 < indices.length ? indices[i + 1] - 1 : len - 1); // включительно
    if (start > end || start < 0 || end >= len) continue;
    if (textElement.isItalic(start)) {
      textElement.setBackgroundColor(start, end, '#ffff00'); // жёлтая
    }
  }
}

function clearItalicInText_(textElement) {
  if (!textElement) return;
  var text = textElement.getText(); if (!text) return;
  var len = text.length; if (len === 0) return;

  var indices = textElement.getTextAttributeIndices();
  for (var i = 0; i < indices.length; i++) {
    var start = indices[i];
    var end = (i + 1 < indices.length ? indices[i + 1] - 1 : len - 1); // включительно
    if (start > end || start < 0 || end >= len) continue;
    if (textElement.isItalic(start)) {
      textElement.setBackgroundColor(start, end, null); // снять фон
    }
  }
}

appscript.json

{
  "timeZone": "Europe/Bucharest",
  "exceptionLogging": "STACKDRIVER",
  "oauthScopes": [
    "https://www.googleapis.com/auth/documents.currentonly",
    "https://www.googleapis.com/auth/script.container.ui"
  ],
  "addOns": {
    "common": {
      "name": "Italic Highlighter",
      "logoUrl": "https://ssl.gstatic.com/docs/doclist/images/icon_11_document_list.png"
    },
    "docs": {
      "homepageTrigger": {
        "runFunction": "onHomepage",
        "enabled": true
      }
    }
  }
}