Initial data commit

Task/Pascals-triangle/JavaScript/pascals-triangle-2.js

@@ -0,0 +1,102 @@
+(function (n) {
+    'use strict';
+
+    // PASCAL TRIANGLE --------------------------------------------------------
+
+    // pascal :: Int -> [[Int]]
+    function pascal(n) {
+        return foldl(function (a) {
+            var xs = a.slice(-1)[0]; // Previous row
+            return append(a, [zipWith(
+                function (a, b) {
+                    return a + b;
+                },
+                append([0], xs),
+                append(xs, [0])
+            )]);
+        }, [
+            [1] // Initial seed row
+        ], enumFromTo(1, n - 1));
+    };
+
+
+    // GENERIC FUNCTIONS ------------------------------------------------------
+
+    // (++) :: [a] -> [a] -> [a]
+    function append(xs, ys) {
+        return xs.concat(ys);
+    };
+
+    // enumFromTo :: Int -> Int -> [Int]
+    function enumFromTo(m, n) {
+        return Array.from({
+            length: Math.floor(n - m) + 1
+        }, function (_, i) {
+            return m + i;
+        });
+    };
+
+    // foldl :: (b -> a -> b) -> b -> [a] -> b
+    function foldl(f, a, xs) {
+        return xs.reduce(f, a);
+    };
+
+    // foldr (a -> b -> b) -> b -> [a] -> b
+    function foldr(f, a, xs) {
+        return xs.reduceRight(f, a);
+    };
+
+    // map :: (a -> b) -> [a] -> [b]
+    function map(f, xs) {
+        return xs.map(f);
+    };
+
+    // min :: Ord a => a -> a -> a
+    function min(a, b) {
+        return b < a ? b : a;
+    };
+
+    // zipWith :: (a -> b -> c) -> [a] -> [b] -> [c]
+    function zipWith(f, xs, ys) {
+        return Array.from({
+            length: min(xs.length, ys.length)
+        }, function (_, i) {
+            return f(xs[i], ys[i]);
+        });
+    };
+
+    // TEST and FORMAT --------------------------------------------------------
+    var lstTriangle = pascal(n);
+
+    // [[a]] -> bool -> s -> s
+    function wikiTable(lstRows, blnHeaderRow, strStyle) {
+        return '{| class="wikitable" ' + (strStyle ? 'style="' + strStyle +
+                '"' : '') + lstRows.map(function (lstRow, iRow) {
+                var strDelim = blnHeaderRow && !iRow ? '!' : '|';
+                return '\n|-\n' + strDelim + ' ' + lstRow.map(function (v) {
+                        return typeof v === 'undefined' ? ' ' : v;
+                    })
+                    .join(' ' + strDelim + strDelim + ' ');
+            })
+            .join('') + '\n|}';
+    }
+
+    var lstLastLine = lstTriangle.slice(-1)[0],
+        lngBase = lstLastLine.length * 2 - 1,
+        nWidth = lstLastLine.reduce(function (a, x) {
+            var d = x.toString()
+                .length;
+            return d > a ? d : a;
+        }, 1) * lngBase;
+
+    return [wikiTable(lstTriangle.map(function (lst) {
+            return lst.join(';;')
+                .split(';');
+        })
+        .map(function (line, i) {
+            var lstPad = Array((lngBase - line.length) / 2);
+            return lstPad.concat(line)
+                .concat(lstPad);
+        }), false, 'text-align:center;width:' + nWidth + 'em;height:' + nWidth +
+        'em;table-layout:fixed;'), JSON.stringify(lstTriangle)].join('\n\n');
+})(7);