Google Doc Word Count + Update Sheet

/* A variable that stores the ID of the Google Document. */
const DOCUMENT_ID = "YourDocIDGoesHere";

/* The ID of the Google Sheet that you want to write the word count to. */
const SHEET_ID = "YourSheetIDGoesHere";

/**
 * It counts the words in a Google Document and writes the word count to a Google Sheet.
 */
function countWords() {
  /* Opening the Google Document with the ID of DOCUMENT_ID. */
  const document = DocumentApp.openById(DOCUMENT_ID);
  /* Setting the word count to 0. */
  let wordCount = 0;

  /* Config for the headings and titles in the document to be excluded them from the word count.
   * This is the same functionality that Google Docs uses for wordcount */
  const searchType = DocumentApp.ElementType.PARAGRAPH;
  const searchHeadings = [
    DocumentApp.ParagraphHeading.HEADING1,
    DocumentApp.ParagraphHeading.HEADING2,
    DocumentApp.ParagraphHeading.HEADING3,
    DocumentApp.ParagraphHeading.HEADING4,
    DocumentApp.ParagraphHeading.HEADING5,
    DocumentApp.ParagraphHeading.HEADING6,
    DocumentApp.ParagraphHeading.TITLE
  ];
  let searchResult = null;


  /* Searching for the headings and titles in the document and excluding them from the word count. */
  while (
    (searchResult = document.getBody().findElement(searchType, searchResult))
  ) {
    const par = searchResult.getElement().asParagraph();
    if (searchHeadings.includes(par.getHeading())) {
      /* Subtracting the number of words in the heading from the word count. */
      wordCount -= par.getText().split(" ").length;
    }
  }


  /* Get all the paragraphs in the document. */
  const paragraphs = document.getBody().getParagraphs();


  /* Loops through all the paragraphs in the document and adds the word count of each paragraph to
  the total word count. */
  for (const paragraph of paragraphs) {
    /* Getting the text of the paragraph. */
    const paragraphText = paragraph.getText();

    /* It splits the paragraph text into an array of words and then counts the number of words in the
    array. */
    wordCount += paragraphText.split(" ").length;
  }

  /* It opens the Google Sheet with the ID of SHEET_ID. */
  const sheet = SpreadsheetApp.openById(SHEET_ID);

  /* Writing the word count to the first cell of the first sheet in the Google Sheet.
   * you can change this to place it whever you need to place the wordcount*/
  const firstSheet = sheet.getSheets()[0];
  const firstCell = firstSheet.getRange("A1");
  firstCell.setValue(wordCount);
}