[MapleStory] Calculate ignore ratio of monster defense.

calcIgnoreMobDefnese.js

/**
 * Calculate the ignore ratio of monster defense.
 *
 * @param base          The base ignore ratio, (Value: 0 ~ 1)
 * @param ignoreItems   The items of ignore addition to be added, (Value: 0 ~ 1)
 */
function calcIgnoreMobDefnese(base, ignoreItems) {

  return Math.floor(ignoreItems.reduce((p, v) => p + (1 - p) * v, base) * 100) / 100;
}

/**
 * e.g. Now my ignore-ratio is 63%, If I get a new armors that add 45% and 15% ignore-ratio.
 */

console.log(calcIgnoreMobDefnese(0.63, [0.45, 0.15]));