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thomascothran/arabify2.js

Last active April 29, 2017 22:18
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Roman Numerals to Arabic Numerals with Tail Calls
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arabify2.js
const nums = {I: 1, V: 5, X: 10, L: 50, C: 100, M: 1000};
const arabify2 = (romNum, sum=0) => {
const [fst, snd, rest] = [romNum[0], romNum[1], romNum.slice(2)];
if (!snd) {return nums[fst] ? nums[fst] + sum : sum;}
else if (nums[snd] > nums[fst]) {
return arabify2(rest, nums[snd] - nums[fst] + sum);
} else {return arabify2(snd + rest, nums[fst] + sum);}
}
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