Probability functions for dropchance calculations

gistfile1.txt

function parseProbability(probability) {
  return Math.min(100, Math.max(0, parseFloat(probability) || 0));
}

function probabilityToPercent(nr) {
  return toFixed(nr * 100) + "%";
}

function probabilityByRuns(probability, runs) {
  return 1 - Math.pow(1 - probability, runs);
}

function dropchanceByRuns(probability, runs) {
  probability = parseProbability(probability);
  runs = Math.max(0, parseInt(runs) || 0);
  return probabilityToPercent(probabilityByRuns(probability / 100, runs));
}