Compare timestamps and copy data

/**
 * @fileoverview Google Apps Script to import new rows from a source sheet to a destination sheet based on unique timestamps.
 *
 * Author: u/IAmMoonie
 * @see https://www.reddit.com/r/GoogleAppsScript/comments/1fi5vw5/compare_timestamps_on_both_sheets_only_copy/
 * Version: 1.0
 */

/**
 * Configuration object for the importNewRequests function.
 *
 * @typedef {Object} Config
 * @property {string} sourceID - The ID of the source Google Sheets spreadsheet.
 * @property {string} formRange - The range in the source sheet to check for new rows, formatted as 'SheetName!A1:R'.
 * @property {string} workingRangeStart - The starting cell in the destination sheet where new rows will be appended.
 * @property {string} timestampColumn - The letter of the column in the source sheet that contains the timestamps.
 */
const config = {
  sourceID: "1MTvMNwNYlKqfgaU_lvv-RqW4Jofs2Z1rrlLRAj4yFzM",
  formRange: "Master!A1:R",
  workingRangeStart: "Working!A1",
  timestampColumn: "A"
};

/**
 * WARNING: Do not edit anything below this point unless you are familiar with Google Apps Script and the purpose of the code.
 */

/**
 * Imports new requests from the source sheet to the destination sheet if they have unique timestamps.
 */
const importNewRequests = () => {
  const sourceSpreadsheet = SpreadsheetApp.openById(config.sourceID);
  const sourceSheet = sourceSpreadsheet.getSheetByName(
    config.formRange.split("!")[0]
  );
  const destSheet = sourceSpreadsheet.getSheetByName(
    config.workingRangeStart.split("!")[0]
  );
  const timestampColIndex = getColumnIndex_(config.timestampColumn);
  const sourceValues = sourceSheet.getRange(config.formRange).getValues();
  const sourceRowCount = sourceValues.length;
  console.info(`Source sheet contains ${sourceRowCount} row(s).`);
  const lastDestRow = getLastNonEmptyRow_(destSheet, timestampColIndex + 1);
  const destRowCount = lastDestRow;
  console.info(`Destination sheet currently has ${destRowCount} row(s).`);
  const destTimestamps = new Set(
    destSheet
      .getRange(1, timestampColIndex + 1, lastDestRow, 1)
      .getValues()
      .flat()
      .map((ts) => new Date(ts).getTime())
  );
  const newRows = [];
  console.info(
    "Checking rows in the source sheet that have a different timestamp compared to the destination sheet"
  );
  sourceValues.forEach((row, index) => {
    const timestamp = new Date(row[timestampColIndex]).getTime();
    console.info(`Checking row ${index + 1}: Timestamp: ${timestamp}`);
    if (timestamp && !destTimestamps.has(timestamp) && !isRowEmpty_(row)) {
      console.info(
        `New row detected with timestamp ${new Date(
          timestamp
        )}, adding to newRows...`
      );
      newRows.push(row);
    } else {
      console.info(
        `Row ${
          index + 1
        } already exists in Working sheet or missing timestamp, skipping.`
      );
    }
  });
  const newRowCount = newRows.length;
  console.info(`${newRowCount} new row(s) meet the requirements.`);
  if (newRowCount > 0) {
    const destRange = destSheet.getRange(
      lastDestRow + 1,
      1,
      newRowCount,
      newRows[0].length
    );
    console.info(`Copying ${newRowCount} new row(s) to the destination sheet.`);
    destRange.setValues(newRows);
  } else {
    console.info("No new rows to copy.");
  }
};

/**
 * Gets the last non-empty row in a specific column of a sheet.
 *
 * @param {Sheet} sheet - The sheet to check.
 * @param {number} column - The column number to check for non-empty rows.
 * @return {number} The index of the last non-empty row.
 */
const getLastNonEmptyRow_ = (sheet, column) => {
  const data = sheet.getRange(1, column, sheet.getLastRow()).getValues();
  for (let i = data.length - 1; i >= 0; i--) {
    if (data[i][0] !== "") {
      return i + 1;
    }
  }
  return 0;
};

/**
 * Checks if a row is empty.
 *
 * @param {Array} row - The row to check.
 * @return {boolean} True if the row is empty, false otherwise.
 */
const isRowEmpty_ = (row) => row.every((cell) => cell === "");

/**
 * Gets the column index from a letter.
 *
 * @param {string} columnLetter - The column letter (e.g., 'A').
 * @return {number} The index of the column (0-based).
 */
const getColumnIndex_ = (columnLetter) =>
  columnLetter.toUpperCase().charCodeAt(0) - 65;