added answer for ch1_q5

Author: kloncentaur8

lib/data-structures/chapter-1/1_5.js

@@ -0,0 +1,35 @@
+module.exports = Strings_1_5 = (function() {
+  return {
+    // Checks if a string can converted to another string with a single edit
+    // Solution #5 from the book.
+    // @param {String} first - first string
+    // @param {String} second - second string
+    // @retuns {Boolean} - true if a string can converted to another string with a single edit
+    oneAway: function(first, second) {
+
+      var skip = true;
+      var s1 = first.length > second.length ? first : second;
+      var s2 = first.length > second.length ? second : first;
+      var diff = s1.length - s2.length;
+      var i1 = 0,
+        i2 = 0;
+
+      if (diff > 1) {
+        return false;
+      }
+      while (i1 < s2.length) {
+        var i2 = i1 + (!skip ? diff : 0);
+        if (s1.charCodeAt(i2) !== s2.charCodeAt(i1)) {
+          if (skip) {
+            i1 = i1 - diff;
+            skip = false;
+          } else {
+            return false;
+          }
+        }
+        i1++;
+      }
+      return true;
+    }
+  };
+}());

test/data-structures/chapter-1/1_5_Spec.js

@@ -0,0 +1,11 @@
+require('../../test_helper');
+describe('1.5 #oneAway', function() {
+  it('returns true if a string can converted to another string with a single edit', function() {
+    expect(Strings_1_5.oneAway('pale', 'ple')).to.be.true;
+    expect(Strings_1_5.oneAway('pales', 'pale')).to.be.true;
+    expect(Strings_1_5.oneAway('pale', 'bale')).to.be.true;
+  });
+  it('returns false if a string can not be converted to another string in a single edit', function() {
+    expect(Strings_1_5.oneAway('pale', 'ble')).to.be.false;
+  });
+});