2016 Update

Task/Substring/JavaScript/substring-2.js

@@ -0,0 +1,57 @@
+(function () {
+    'use strict';
+
+    //  take :: Int -> Text -> Text
+    function take(n, s) {
+        return s.substr(0, n);
+    }
+
+    //  drop :: Int -> Text -> Text
+    function drop(n, s) {
+        return s.substr(n);
+    }
+
+
+    // init :: Text -> Text
+    function init(s) {
+        var n = s.length;
+        return (n > 0 ? s.substr(0, n - 1) : undefined);
+    }
+
+    // breakOn :: Text -> Text -> (Text, Text)
+    function breakOn(strPattern, s) {
+        var i = s.indexOf(strPattern);
+        return i === -1 ? [strPattern, ''] : [s.substr(0, i), s.substr(i)];
+    }
+
+
+    var str = '一二三四五六七八九十';
+
+
+    return JSON.stringify({
+
+        'from n in, of m length': (function (n, m) {
+            return take(m, drop(n, str));
+        })(4, 3),
+
+
+        'from n in, up to end' :(function (n) {
+            return drop(n, str);
+        })(3),
+
+
+        'all but last' : init(str),
+
+
+        'from matching char, of m length' : (function (pattern, s, n) {
+            return take(n, breakOn(pattern, s)[1]);
+        })('五', str, 3),
+
+
+        'from matching string, of m length':(function (pattern, s, n) {
+            return take(n, breakOn(pattern, s)[1]);
+        })('六七', str, 4)
+
+    }, null, 2);
+
+})();

Task/Substring/JavaScript/substring-3.js

@@ -0,0 +1,7 @@
+{
+  "from n in, of m length": "五六七",
+  "from n in, up to end": "四五六七八九十",
+  "all but last": "一二三四五六七八九",
+  "from matching char, of m length": "五六七",
+  "from matching string, of m length": "六七八九"
+}