Initial data commit

Task/Run-length-encoding/JavaScript/run-length-encoding-1.js

@@ -0,0 +1,15 @@
+function encode(input) {
+    var encoding = [];
+    var prev, count, i;
+    for (count = 1, prev = input[0], i = 1; i < input.length; i++) {
+        if (input[i] != prev) {
+            encoding.push([count, prev]);
+            count = 1;
+            prev = input[i];
+        }
+        else
+            count ++;
+    }
+    encoding.push([count, prev]);
+    return encoding;
+}

Task/Run-length-encoding/JavaScript/run-length-encoding-2.js

@@ -0,0 +1,5 @@
+function encode_re(input) {
+    var encoding = [];
+    input.match(/(.)\1*/g).forEach(function(substr){ encoding.push([substr.length, substr[0]]) });
+    return encoding;
+}

Task/Run-length-encoding/JavaScript/run-length-encoding-3.js

@@ -0,0 +1,5 @@
+function decode(encoded) {
+    var output = "";
+    encoded.forEach(function(pair){ output += new Array(1+pair[0]).join(pair[1]) })
+    return output;
+}

Task/Run-length-encoding/JavaScript/run-length-encoding-4.js

@@ -0,0 +1,51 @@
+(() => {
+    'use strict';
+
+    // runLengthEncode :: String -> [(Int, Char)]
+    const runLengthEncoded = s =>
+        group(s.split('')).map(
+            cs => [cs.length, cs[0]]
+        );
+
+    // runLengthDecoded :: [(Int, Char)] -> String
+    const runLengthDecoded = pairs =>
+        pairs.map(([n, c]) => c.repeat(n)).join('');
+
+
+    // ------------------------TEST------------------------
+    const main = () => {
+        const
+            xs = 'WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWW' +
+            'WWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW',
+            ys = runLengthEncoded(xs);
+
+        console.log('From: ', show(xs));
+        [ys, runLengthDecoded(ys)].forEach(
+            x => console.log('  ->  ', show(x))
+        )
+    };
+
+    // ----------------------GENERIC-----------------------
+
+    // group :: [a] -> [[a]]
+    const group = xs => {
+        // A list of lists, each containing only equal elements,
+        // such that the concatenation of these lists is xs.
+        const go = xs =>
+            0 < xs.length ? (() => {
+                const
+                    h = xs[0],
+                    i = xs.findIndex(x => h !== x);
+                return i !== -1 ? (
+                    [xs.slice(0, i)].concat(go(xs.slice(i)))
+                ) : [xs];
+            })() : [];
+        return go(xs);
+    };
+
+    // show :: a -> String
+    const show = JSON.stringify;
+
+    // MAIN ---
+    return main();
+})();

Task/Run-length-encoding/JavaScript/run-length-encoding-5.js

@@ -0,0 +1,3 @@
+const rlEncode = (s: string) => s.match(/(.)\1*/g).reduce((result,char) => result+char.length+char[0],"")
+const rlValidate = (s: string) => /^(\d+\D)+$/.test(s)
+const rlDecode = (s: string) => rlValidate(s) ? s.match(/(\d[a-z\s])\1*/ig).reduce((res,p) => res+p[p.length-1].repeat(parseInt(p)),"") : Error("Invalid rl")