Dice-rolling program. Run with Lodash.

dice.js

/* [41] dice.js: Utilities for dice-rolling. Intended for large numbers of
 * divisions in Risk.
 */

/*** DEPENDENCIES ***
 * lodash
 */

/*** USAGE ***
 * rollDice(): Run rollDice() with an array of the number of dices to roll.
 * For example, rollDice([1, 2]) will roll a die, and two dice, and return the
 * result. Passing a number will cast it into an array.
 *
 * highest(): Pick the highest element in an array.
 */

/*** LICENSE ***
 * This code is licensed under the Unlicense.
 *
 * > This is free and unencumbered software released into the public domain.
 * >
 * > Anyone is free to copy, modify, publish, use, compile, sell, or
 * > distribute this software, either in source code form or as a compiled
 * > binary, for any purpose, commercial or non-commercial, and by any
 * > means.
 * >
 * > In jurisdictions that recognize copyright laws, the author or authors
 * > of this software dedicate any and all copyright interest in the
 * > software to the public domain. We make this dedication for the benefit
 * > of the public at large and to the detriment of our heirs and
 * > successors. We intend this dedication to be an overt act of
 * > relinquishment in perpetuity of all present and future rights to this
 * > software under copyright law.
 * >
 * > THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * > EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * > MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * > IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * > OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * > ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * > OTHER DEALINGS IN THE SOFTWARE.
 * >
 * > For more information, please refer to <http://unlicense.org/>
 */

/*** AUTHORS ***
 * This code was written by thatlittlegit (thatlittlegit@outlook.com).
 */
// code start

// Check for dependencies
if (!_.random) {
	throw new Error('Missing dependencies for dice.js');
}

/**
  * Main dice-rolling function. Rolls dice as specified in `rolls` and
  * returns the reduced dice rolls.
  *
  * @param {Number|Array[Number]} rolls The selection of dice rolls.
  * @returns {Array[Number]} The result of the rolls
  * @example
  *   rollDice(1);
  *   // => [4]
  *   rollDice([1]);
  *   // => [6]
  *   rollDice([20, 12]);
  *   // => [60, 48]
  */
function rollDice(rolls) {
	return (Array.isArray(rolls) ? rolls : [rolls])
		.map(rollCount => (
			Array.from(Array(rollCount))
				.map(() => (_.random || random)(1, 6))
				.reduce((x, y) => x + y)
		));
}

/**
  * When given an array of values, returns the largest one.
  *
  * @param {Array} input The array to reduce.
  * @returns {Array[Number]} The largest value and its corresponding index.
  * @example
  *   highest([1, 2, 5]);
  *   // => 5
  *   highest([5, 3, 2]);
  *   // => 5
  */
function highest(input) {
	const result = Array.from(input)
		.reduce((current, old, index) => current > old
			? current
			: old);

	return [
		result,
		input.indexOf(result)
	];
}