fix(*): handle no match condition

winkjs · Sep 27, 2017 · 2856d2a · 2856d2a
1 parent e2251dd
commit 2856d2a
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Showing 3 changed files with 16 additions and 4 deletions.
diff --git a/README.md b/README.md
@@ -54,8 +54,10 @@ Original Reference: UNIMATCH:
 **Examples**
 
 ```javascript
-// returns { distance: 0.08333333333333337, similarity: 0.9166666666666666 }
 jaro( 'daniel', 'danielle' );
+// -> { distance: 0.08333333333333337, similarity: 0.9166666666666666 }
+jaro( 'god', 'father' );
+// -> { distance: 1, similarity: 0 }
 ```
 
 Returns **[object](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object)** containing `distance` and `similarity` values between 0 and 1.

diff --git a/src/wink-jaro-distance.js b/src/wink-jaro-distance.js
@@ -38,8 +38,10 @@
  * @return {object} - containing `distance` and `similarity` values between 0 and 1.
  *
  * @example
- * // returns { distance: 0.08333333333333337, similarity: 0.9166666666666666 }
  * jaro( 'daniel', 'danielle' );
+ * // -> { distance: 0.08333333333333337, similarity: 0.9166666666666666 }
+ * jaro( 'god', 'father' );
+ * // -> { distance: 1, similarity: 0 }
  */
 var jaro = function ( s1, s2 ) {
   // On the basis of the length of `s1` and `s2`, the shorter length string will
@@ -104,8 +106,10 @@ var jaro = function ( s1, s2 ) {
     }
   }
   transposes /= 2;
-  // Compute similarity.
-  smlrty = ( ( matches / shortLen ) + ( matches / longLen ) + ( ( matches - transposes ) / matches ) ) / 3;
+  // Compute similarity; if no `matches` means similarity is 0!
+  smlrty = ( matches === 0 ) ?
+            0 :
+            ( ( matches / shortLen ) + ( matches / longLen ) + ( ( matches - transposes ) / matches ) ) / 3;
   return {
     distance: 1 - smlrty,
     similarity: smlrty

diff --git a/test/wink-jaro-distance-specs.js b/test/wink-jaro-distance-specs.js
@@ -45,6 +45,12 @@ describe( 'jaro()', function () {
     { whenInputIs: [ 'abcd', 'dcba' ], expectedOutputIs: { similarity: 0.5, distance: 0.5 } },
     { whenInputIs: [ 'washington', 'notgnihsaw' ], expectedOutputIs: { similarity: 0.43333333333333335, distance: 1 - 0.43333333333333335 } },
     { whenInputIs: [ 'washington', 'washingtonx' ], expectedOutputIs: { similarity: 0.9696969696969697, distance: 1 - 0.9696969696969697 } },
+    // No match case
+    { whenInputIs: [ 'sat', 'urn' ], expectedOutputIs: { similarity: 0, distance: 1 } },
+    // Empty string case
+    { whenInputIs: [ '', '' ], expectedOutputIs: { similarity: 1, distance: 0 } },
+    // One of them is Empty
+    { whenInputIs: [ '', 'urn' ], expectedOutputIs: { similarity: 0, distance: 1 } },
   ];
 
   tests.forEach( function ( t ) {