True Range (TR)

/**

 * Calculates the True Range (TR) values

 *

 * @param {array} data - an array where the first column is the  dates, and subsequent columns for  open, high, low, close and volume.  

 * @returns {Array<Array>} - A 2D array containing dates and their corresponding True Range values.

 *

 * @customfunction

 */

  

function TR(data) {

  // Preprocess data using getData

  const processedData = getData(data);

  // Extract columns from the processed data

  const dates = processedData.slice(1).map(row => row[0]);

  const highs = processedData.slice(1).map(row => row[2]);

  const lows = processedData.slice(1).map(row => row[3]);

  const closes = processedData.slice(1).map(row => row[4]);

  

  // Calculate True Range values

  let trueRanges = [["Date", "TR"]]; // Include headers

  for (let i = 1; i < highs.length; i++) {

    let tr = Math.max(highs[i], closes[i - 1]) - Math.min(lows[i], closes[i - 1]);

    trueRanges.push([dates[i], tr]);

  }

  

  return trueRanges;

}

  

/**

 *

 * @param {Array<Array>} data - A 2D array of cell values to process. The first row should contain headers.

 * @returns {Array<Array>} - A 2D array where the first row contains headers and subsequent rows contain processed data.

 *

 * @customfunction

 *

 */

  

function getData(data) {

  if (!Array.isArray(data) || data.length === 0) {

    throw new Error("Input data must be a non-empty array.");

  }

  
  

  // Check if the first row contains headers

  const headers = Array.isArray(data[0]) && data[0].every(item => typeof item === "string")

    ? data[0]

    : null;

  

  if (!headers) {

    // If no headers, assume the first column is the date column and process data

    return data.map(row => row.map((value, index) => {

      return index === 0 ? new Date(value) : parseFloat(value);

    }));

  }

  

  // Process rows with headers

  return [headers, ...data.slice(1).map(row => headers.map((header, index) => {

    const key = header.toLowerCase();

    return key === "date" ? new Date(row[index]) : parseFloat(row[index]) || row[index];

  }))];

}