optimizing relativeTo() results - closes #95

README.md

@@ -209,7 +209,7 @@ URI.js is published under the [MIT license](http://www.opensource.org/licenses/m
 
 ### `[dev-version]` (master branch) ###
 
-* optimize [`relativeTo()`](http://medialize.github.com/URI.js/docs.html#relativeto) results - ([Issue #78](https://github.com/medialize/URI.js/issues/78))
+* optimize [`relativeTo()`](http://medialize.github.com/URI.js/docs.html#relativeto) results - ([Issue #78](https://github.com/medialize/URI.js/issues/78), [Issue #95](https://github.com/medialize/URI.js/issues/95))
 * removing obsolete code fragments from `URI.parse()` and `relativeTo()` - ([Issue #100](https://github.com/medialize/URI.js/issues/100))
 * adding setting `URI.escapeQuerySpace` to control if query string should escape spaces using `+` or `%20` - ([Issue #74](https://github.com/medialize/URI.js/issues/74))
 * updating [Punycode.js](https://github.com/bestiejs/punycode.js/) to version 1.2.3

docs.html

@@ -866,12 +866,26 @@ <h3 id="relativeto">relativeTo()</h3>
 // -&gt; "foo/world.html"
 
 // absolute URLs are passed through unchanged
-URI("http://example.org/world.html").absoluteTo("http://google.com/baz");
+URI("http://example.org/world.html")
+  .absoluteTo("http://google.com/baz");
 // -&gt; "http://example.org/world.html"
 
 // absolute URLs relative to absolute URLs
-URI("http://example.org/world.html").clone().authority("").absoluteTo("http://google.com/baz");
-// -&gt; "http://google.com/world.html"</pre>
+URI("http://example.org/world.html").clone().authority("")
+  .absoluteTo("http://google.com/baz");
+// -&gt; "http://google.com/world.html"
+
+// equal URLs are relative by empty string
+URI("http://www.example.com:8080/dir/file")
+  .relativeTo('http://www.example.com:8080/dir/file')
+  .toString();
+// -&gt; ""
+
+// relative on fragment and query string as well
+URI("http://www.example.com:8080/dir/file?foo=bar#abcd")
+  .relativeTo('http://www.example.com:8080/dir/file')
+  .toString();
+// -&gt; "?foo=bar#abcd"</pre>
     <p>.relativeTo() and .absoluteTo() reverse each other.</p>
 
     <h3 id="absoluteto">absoluteTo()</h3>

src/URI.js

@@ -1757,7 +1757,7 @@ p.absoluteTo = function(base) {
 };
 p.relativeTo = function(base) {
     var relative = this.clone().normalize();
-    var relativeParts, baseParts, common;
+    var relativeParts, baseParts, common, relativePath, basePath;
 
     if (relative._parts.urn) {
         throw new Error('URNs do not have any generally defined hierarchical components');
@@ -1766,12 +1766,14 @@ p.relativeTo = function(base) {
     base = new URI(base).normalize();
     relativeParts = relative._parts;
     baseParts = base._parts;
+    relativePath = relative.path();
+    basePath = base.path();
 
-    if (relative.path().charAt(0) !== '/') {
+    if (relativePath.charAt(0) !== '/') {
         throw new Error('URI is already relative');
     }
 
-    if (base.path().charAt(0) !== '/') {
+    if (basePath.charAt(0) !== '/') {
         throw new Error('Cannot calculate a URI relative to another relative URI');
     }
 
@@ -1794,6 +1796,11 @@ p.relativeTo = function(base) {
         return relative.build();
     }
 
+    if (relativePath === basePath) {
+        relativeParts.path = '';
+        return relative.build();
+    }
+
     // determine common sub path
     common = URI.commonPath(relative.path(), base.path());
 
@@ -1806,7 +1813,7 @@ p.relativeTo = function(base) {
         .substring(common.length)
         .replace(/[^\/]*$/, '')
         .replace(/.*?\//g, '../');
-    
+
     relativeParts.path = parents + relativeParts.path.substring(common.length);
 
     return relative.build();

test/test.js

@@ -1179,16 +1179,31 @@ test("relativeTo", function() {
             url: 'http://example.org:8081/foo/bar',
             base: 'http://example.org/foo/bar',
             result: '//example.org:8081/foo/bar'
+        }, {
+            name: 'same path - fragment',
+            url: 'http://www.example.com:8080/dir/file#abcd',
+            base: 'http://www.example.com:8080/dir/file',
+            result: '#abcd'
+        }, {
+            name: 'same path - query',
+            url: 'http://www.example.com:8080/dir/file?abcd=123',
+            base: 'http://www.example.com:8080/dir/file',
+            result: '?abcd=123'
+        }, {
+            name: 'same path - query and fragment',
+            url: 'http://www.example.com:8080/dir/file?abcd=123#alpha',
+            base: 'http://www.example.com:8080/dir/file',
+            result: '?abcd=123#alpha'
         }, {
             name: 'already relative',
             url: 'foo/bar',
             base: '/foo/',
-            throws: true
+            'throws': true
         }, {
             name: 'relative base',
             url: '/foo/bar',
             base: 'foo/',
-            throws: true
+            'throws': true
         }
     ];
 
@@ -1204,7 +1219,7 @@ test("relativeTo", function() {
             caught = true;
         }
 
-        if (t.throws) {
+        if (t['throws']) {
             ok(caught, t.name + " should throw exception");
         } else {
             ok(!caught, t.name + " should not throw exception");