Sum each row / Sum each header

/**
* Returns the sum of each row in a multiple column dataset.
*
* @param {A2:D10} data The input data
* @return {array} sums.
* @customfunction
*/
function SUM_EACH_ROW(data) {
  const results = []

  data.forEach(row => {
    let n = 0
    row.forEach(col => {
      if (typeof col == 'number') {
        n += col
      }
    })
    if (n == 0) {
      results.push([""])
    } else {
      results.push([n])
    }
  })

  return results
}

/**
* Returns the sum of each column with column headers.
*
* @param {A1:D10} data The input data (including the headers)
* @return {array} sums.
* @customfunction
*/
function SUM_EACH_COL(data){
  const resultsObj = {}

  data[0].forEach((header, i) => {
    resultsObj[i] = {header, sum: 0}
  })

  data.unshift()

  data.forEach((row) => {
    row.forEach((col, i) => {
      if (typeof col == 'number') {
        resultsObj[i].sum += col
      }
    })
  })

  return Object.values(resultsObj).map(res => {
    const { header, sum } = res
    return [header, sum]
  })

}