diff options
| -rw-r--r-- | __tests__/dice.test.js | 30 | ||||
| -rw-r--r-- | src/dice.js | 20 |
2 files changed, 49 insertions, 1 deletions
diff --git a/__tests__/dice.test.js b/__tests__/dice.test.js index 1274b3d..1be0744 100644 --- a/__tests__/dice.test.js +++ b/__tests__/dice.test.js @@ -5,7 +5,8 @@ const { add, subtract, negative, - explode + explode, + keepHigh } = require('../src/dice.js') const defaultNumberRolls = 500 @@ -378,3 +379,30 @@ describe('exploding dice', () => { }) }) }) + +describe('keep', () => { + describe('1K2d20', () => { + const die = keepHigh(constant(1), d(constant(2), constant(20))) + + testDie(die, { + diceCount: 1, + average: { + average: 13.825 + }, + variance: { + variance: 22.104 + }, + bounds: { + low: 1, + high: 20, + expectLow: true, + expectHigh: true + } + }, 800) + }) + + describe('2K1d20', () => { + const die = keepHigh(constant(2), d(constant(1), constant(20))) + testDie(die, basicDieTestSpecs(1, 20)) + }) +}) diff --git a/src/dice.js b/src/dice.js index b60af68..5e3b975 100644 --- a/src/dice.js +++ b/src/dice.js @@ -56,6 +56,25 @@ const explode = (die1, die2) => { } } +const keepHigh = (die1, die2) => { + return () => { + const numberToKeep = roll(die1) + let rolls = die2().map(die => [die, die()]) + rolls.sort((a, b) => (a[1] - b[1])).reverse() + return rolls.slice(0, numberToKeep).map(pair => { + let returnedOriginal = false + return () => { + if (!returnedOriginal) { + returnedOriginal = true + return pair[1] + } else { + return pair[0]() + } + } + }) + } +} + exports.pool = pool exports.roll = roll exports.constant = constant @@ -64,3 +83,4 @@ exports.add = add exports.subtract = subtract exports.negative = negative exports.explode = explode +exports.keepHigh = keepHigh |