RosettaCodeData/Task/Roman-numerals-Encode/JavaScript/roman-numerals-encode-2.js

50 lines
1.3 KiB
JavaScript

(function () {
'use strict';
// If the Roman is a string, pass any delimiters through
// (Int | String) -> String
function romanTranscription(a) {
if (typeof a === 'string') {
var ps = a.split(/\d+/),
dlm = ps.length > 1 ? ps[1] : undefined;
return (dlm ? a.split(dlm)
.map(function (x) {
return Number(x);
}) : [a])
.map(roman)
.join(dlm);
} else return roman(a);
}
// roman :: Int -> String
function roman(n) {
return [[1000, "M"], [900, "CM"], [500, "D"], [400, "CD"], [100,
"C"], [90, "XC"], [50, "L"], [40, "XL"], [10, "X"], [9,
"IX"], [5, "V"], [4, "IV"], [1, "I"]]
.reduce(function (a, lstPair) {
var m = a.remainder,
v = lstPair[0];
return (v > m ? a : {
remainder: m % v,
roman: a.roman + Array(
Math.floor(m / v) + 1
)
.join(lstPair[1])
});
}, {
remainder: n,
roman: ''
}).roman;
}
// TEST
return [2016, 1990, 2008, "14.09.2015", 2000, 1666].map(
romanTranscription);
})();