Another update from ingydotnet^djgoku

Task/Floyds-triangle/JavaScript/floyds-triangle-1.js

@@ -0,0 +1,78 @@
+// Floyd triangles of 5 and 14 rows
+// right-aligned monospaced columns (nMargin allows for extra spacing)
+// () --> s
+function main() {
+    // minimum space between numbers - adjust for visual preference
+    var nMargin = 1;
+
+    // Formatted strings for Floyd's triangles of 5 and 14 rows
+    return (function (lstN) {
+        return lstN.map(function (nFloydRows) {
+            var lstRows = floydIntegerLists(nFloydRows),
+                iLast = nFloydRows - 1;
+
+            return colsSpacedRight(
+                lstRows,
+                // Minimum space required per number cell
+                // nMargin more than the width of the final number
+                lstRows[iLast][iLast].toString().length + nMargin
+            )
+        }).join('\n\n');
+    })([5, 14]);
+}
+
+// n Floyd's triangle rows
+// n --> [[n]]
+function floydIntegerLists(nRows) {
+
+    // Full integer list folded into list of rows
+    // [n] --> [[n]]
+    return (function triangleNumbers(lstInt, startWidth) {
+        var n = startWidth || 1;
+
+        return n > lstInt.length ? [] : [lstInt.slice(0, n)].concat(
+            triangleNumbers(lstInt.slice(n), n + 1)
+        )
+    })(
+        range(
+            1,
+            Math.floor(
+                (nRows * nRows) / 2
+            ) + Math.ceil(
+                nRows / 2
+            )
+        )
+    );
+}
+
+// list of list of numbers --> lines of fixed right-aligned col width
+// [[n]] --> s
+function colsSpacedRight(lstLines, nColWidth) {
+    return lstLines.reduce(
+        function (s, line) {
+            return s + line.map(function (n) {
+                return rightAligned(n, nColWidth)
+            }).join('') + '\n';
+        }, ''
+    )
+}
+
+// range(1, 20) --> [1..20]
+function range(m, n) {
+    return Array.apply(null, Array(n - m + 1)).map(
+        function (x, i) {
+            return m + i;
+        }
+    );
+}
+
+// Integer as right-padded string of given width
+// n --> n --> s
+function rightAligned(n, width) {
+    var strN = n.toString();
+    return Array(width - strN.length + 1).join(' ') + strN;
+}
+
+console.log( // if the context is a browser
+    main()
+);