Calculate chi square values from n x m table

chi-square-value.js

function chiSquareValue(values, separateBy = 2) {
  if (values.length % separateBy !== 0) {
    throw new Error(`Illegal separation rule. values.length ${valus.length} cannot be divided by ${separateBy}.`)
  }
  const sum = values.reduce((acc, val) => acc + val, 0)
  const rowSums = []
  const colSums = []
  return values.reduce((chiSq, val, i) => {
    const row = Math.floor(i / separateBy)
    const col = i % separateBy
    if (rowSums[row] == null) {
      rowSums[row] = values.slice(row * separateBy, (row + 1) * separateBy).reduce((acc, val) => acc + val, 0)
    }
    if (colSums[col] == null) {
      colSums[col] = values.filter((val, j) => j % separateBy === col).reduce((acc, val) => acc + val, 0)
    }
    const rowSum = rowSums[row]
    const colSum = colSums[col]
    const expected = rowSum * colSum / sum
    const chiSqPart = Math.pow(val - expected, 2) / expected
    console.log({ i, val, row, col, rowSum, colSum, expected, chiSqPart })
    return chiSq + chiSqPart
  }, 0)
}

module.exports = chiSquareValue

Just remove console.log!