September 2017 Update

Task/Roman-numerals-Decode/JavaScript/roman-numerals-decode-6.js

@@ -0,0 +1,35 @@
+(() => {
+    // romanValue :: String -> Int
+    const romanValue = s =>
+        s.length ? (() => {
+            const parse = [].concat(
+                ...glyphs.map(g => 0 === s.indexOf(g) ? (
+                    [dctTrans[g], s.substr(g.length)]
+                ) : [])
+            );
+            return parse[0] + romanValue(parse[1]);
+        })() : 0;
+
+    // dctTrans :: {romanKey: Integer}
+    const dctTrans = {
+        M: 1E3,
+        CM: 900,
+        D: 500,
+        CD: 400,
+        C: 100,
+        XC: 90,
+        L: 50,
+        XL: 40,
+        X: 10,
+        IX: 9,
+        V: 5,
+        IV: 4,
+        I: 1
+    };
+
+    // glyphs :: [romanKey]
+    const glyphs = Object.keys(dctTrans);
+
+    // TEST -------------------------------------------------------------------
+    return ["MCMXC", "MDCLXVI", "MMVIII", "MMMM"].map(romanValue);
+})();