Add solutions to string tests.

Author: jamesplease

app/strings.js

@@ -0,0 +1,76 @@
+if (typeof define !== 'function') { var define = require('amdefine')(module); }
+
+define(function() {
+  return {
+    reduceString: function(str, amount) {
+      var outputString = '';
+      var character;
+      var inputStrArray = str.split('');
+
+      // we use this object to keep a count of the number of times
+      // each character appears in the string
+      var characterCount = {};
+
+      for (var i = 0, len = inputStrArray.length; i < len; i++) {
+        character = inputStrArray[i];
+
+        // if the character isn't in our counting object yet,
+        // then this is the first occurrence
+        if (typeof characterCount[character] === 'undefined') {
+          characterCount[character] = 1;
+        }
+
+        // otherwise, we already have it, so we add one to our count
+        else {
+          characterCount[character] = characterCount[character] + 1;
+        }
+
+        // anytime our count comes in below the amount specified, we
+        // include that character in our output
+        if (characterCount[character] <= amount) {
+          outputString += character;
+        }
+      }
+
+      return outputString;
+    },
+
+    wordWrap: function(str, cols) {
+      var words = str.split(' ');
+      var outputString = '';
+      var currentLength = 0;
+      var word;
+      var separator;
+
+      for (var i = 0, len = words.length; i < len; i++) {
+        word = words[i];
+        currentLength += word.length;
+
+        // if its the first word, then we don't need a separator
+        if (i === 0) {
+          separator = '';
+        }
+
+        // if we've gone past our `cols` length, then we start a new line
+        else if (currentLength > cols) {
+          currentLength = word.length;
+          separator = '\n';
+        }
+
+        // otherwise, we haven't gone over the line length and we separate
+        // the words with a space
+        else {
+          separator = ' ';
+        }
+
+        outputString += separator + word;
+      }
+
+      return outputString;
+    },
+
+    reverseString: function(str) {
+      return str.split('').reverse().join('');
+    }
+  };
+});