Set Google Docs Heading

SetGoogleDocsHeading.js

// reference:
// https://developers.google.com/apps-script/reference/document/body#getchildindexchild
// https://developers.google.com/apps-script/reference/document/body#getattributes
// https://stackoverflow.com/questions/8273047/javascript-function-similar-to-python-range

function log(message) {
  //Logger.log(message)
}

function getTextLineFromBody(theBody, index) {
  bodyAsTextLines = theBody.getText().split("\n");
  return bodyAsTextLines[index]
}

function countWordsInLine(textLine) {
  a = textLine.split(" ")
  //log("array from line: [" + a + "]")
  b = a.length
  //log("length of line/array is: [" + b + "]")
  return b
}

function setHeading(theBody, index) {
  var element = theBody.getChild(index)
  log("1. Element (type) is: [" + element + "]");
  log("2. Element (type) is: [" + element.getType().toString() + "]");
  if (element.getType().toString() === 'TABLE_OF_CONTENTS') {
    // heading does not apply to TOC: early return
   return;
  }
  var line = getTextLineFromBody(theBody, index)
  //log(line)

  let wordCountForLine = countWordsInLine(line)
  log("Count in line: [" + wordCountForLine + "]")

  // a paragraph is a header if there are between 1 and
  // 9 words inclusive
  if (0 < wordCountForLine && wordCountForLine < 10) {
    log("candidate line at index [" + index + "]")
    log(element)
    element.setHeading(DocumentApp.ParagraphHeading.HEADING2)
  }
}

function setHeadings() {
  var body = DocumentApp.getActiveDocument().getBody();
  var numChildrenInBody = body.getNumChildren()

  log("There are " + body.getNumChildren() + " elements in the document body.");

  for (let i of Array(numChildrenInBody).keys()) {
    setHeading(body, i)
  }
}