u/icwiener69420 - Mail merge

function myFunction() {

  var docTemplateID = "big long hex value here - removed for reddit post";
  var docFinalID = "big long hex value here - removed for reddit post";
  var docTemplate = DocumentApp.openById(docTemplateID);
  var docFinal = DocumentApp.openById(docFinalID);
  var templateParagraphs = docTemplate.getBody().getParagraphs();

  var wsID = "big long hex value here - removed for reddit post";
  var ws = SpreadsheetApp.openById(wsID).getSheetByName("waterfalls");
  var data = ws.getRange(2, 1, ws.getLastRow() - 1, 20).getValues();

  docFinal.getBody().clear();

  var counter = 0
  var steps = 140

  do {
    for (i = counter; i < (steps + counter); i++) {
      if (i == data.length) { break; }
      let r = data[i]
      createMailMerge(r[0], r[1], r[2], r[18], r[17], r[5], r[6], r[12], r[11], r[19], templateParagraphs, docFinal);
    }
    docFinal.saveAndClose()
    counter += steps
  } while (counter < data.length)

}

function createMailMerge(fallsName, fallsRegion, fallsCounty, fallsTown, fallsWaterBody, fallsLat, fallsLong, fallsDrones, fallsBobText, fallsNotes, templateParagraphs, docFinal) {

  templateParagraphs.forEach(function (p) {
    docFinal.getBody().appendParagraph(
      p.copy()
        .replaceText("{waterfall_name}", fallsName)
        .replaceText("{region}", fallsRegion)
        .replaceText("{county}", fallsCounty)
        .replaceText("{town}", fallsTown)
        .replaceText("{body_of_water}", fallsWaterBody)
        .replaceText("{lat}", fallsLat)
        .replaceText("{long}", fallsLong)
        .replaceText("{drones}", fallsDrones)
        .replaceText("{bob_fulltext}", fallsBobText)
        .replaceText("{notes}", fallsNotes)
    );
  });

  docFinal.save
}