Split integer by ratios

splitIntegerByRatios.js

function allocateInt(amount, ratios) {
  if (ratios.length == 1) {
    return [amount]
  } else {
      const rs = [...ratios]
      const divisor = rs.reduce((a,i)=>a+i)
      const thisAmount = Math.round(amount*rs.shift()/divisor)
      return [
        thisAmount,
        ...allocateInt(amount-thisAmount, rs)
      ]
  }
}