added answer for ch1_q6

Author: kloncentaur8

lib/data-structures/chapter-1/1_6.js

@@ -0,0 +1,27 @@
+module.exports = Strings_1_6 = (function() {
+  return {
+    // Generates a compressed string with a trailing letter count
+    // Solution #6 from the book.
+    // @param {String} str - The string to compress
+    // @retuns {Boolean} - a compressed string with a trailing letter count, if the string does not become smaller the orginal string is returned
+    stringCompression: function(str) {
+      var index = 0,
+        count = 1;
+
+      var seed = str.charAt(0);
+      var newStr = '';
+
+      while (index - 1 < str.length) {
+        if (seed === str.charAt(index + 1)) {
+          count++;
+        } else {
+          newStr += (seed + count);
+          count = 1;
+          seed = str.charAt(index + 1);
+        }
+        index++;
+      }
+      return newStr.length < str.length ? newStr : str;
+    }
+  };
+}());

test/data-structures/chapter-1/1_6_Spec.js

@@ -0,0 +1,7 @@
+require('../../test_helper');
+describe('1.6 #stringCompression', function() {
+  it('returns a compressed string', function() {
+    expect(Strings_1_6.stringCompression('aabcccccaaa')).to.be.equal('a2b1c5a3');
+    expect(Strings_1_6.stringCompression('abcdef')).to.be.equal('abcdef');
+  });
+});