fix(Angular.js): handle duplicate params in parseKeyValue/toKeyValue

parseKeyValue and toKeyValue can now handle duplicate values in the query.
```
?x=1&x=2 <-> {x:[1,2]}
```

The algorithm looks like:
    1)parseKeyValue looks for presence of obj[key]
    2)detects and replaces obj[key] with [obj[key],val]
    3)then pushes more duplicates if necessary
    4)toKeyValue decodes array correctly
    5)(not changed)$location.search({param: 'key'}) still replaces if necessary
    6)(not changed)$location.search({param: ['key1', 'key2']}) sets the url with duplicates

BREAKING CHANGE: Before this change:
- `parseKeyValue` only took the last key overwriting all the previous keys;
- `toKeyValue` joined the keys together in a comma delimited string.
This was deemed buggy behavior. If your server relied on this behavior
then either the server should be fixed or a simple serialization of
the array should be done on the client before passing it to $location.

Author: joshkurz

src/Angular.js

@@ -850,7 +850,14 @@ function parseKeyValue(/**string*/keyValue) {
       key_value = keyValue.split('=');
       key = tryDecodeURIComponent(key_value[0]);
       if ( isDefined(key) ) {
-        obj[key] = isDefined(key_value[1]) ? tryDecodeURIComponent(key_value[1]) : true;
+        var val = isDefined(key_value[1]) ? tryDecodeURIComponent(key_value[1]) : true;
+        if (!obj[key]) {
+          obj[key] = val;
+        } else if(isArray(obj[key])) {
+          obj[key].push(val);
+        } else {
+          obj[key] = [obj[key],val];
+        }
       }
     }
   });
@@ -860,7 +867,13 @@ function parseKeyValue(/**string*/keyValue) {
 function toKeyValue(obj) {
   var parts = [];
   forEach(obj, function(value, key) {
+    if (isArray(value)) {
+      forEach(value, function(arrayValue) {
+        parts.push(encodeUriQuery(key, true) + (arrayValue === true ? '' : '=' + encodeUriQuery(arrayValue, true)));
+      });
+    } else {
     parts.push(encodeUriQuery(key, true) + (value === true ? '' : '=' + encodeUriQuery(value, true)));
+    }
   });
   return parts.length ? parts.join('&') : '';
 }

src/ng/location.js

@@ -344,7 +344,8 @@ LocationHashbangInHtml5Url.prototype =
    *
    * Change search part when called with parameter and return `$location`.
    *
-   * @param {string|object<string,string>=} search New search params - string or hash object
+   * @param {string|Object.<string>|Object.<Array.<string>>} search New search params - string or hash object. Hash object
+   *    may contain an array of values, which will be decoded as duplicates in the url.
    * @param {string=} paramValue If `search` is a string, then `paramValue` will override only a
    *    single search parameter. If the value is `null`, the parameter will be deleted.
    *

test/AngularSpec.js

@@ -318,10 +318,21 @@ describe('angular', function() {
       expect(parseKeyValue('invalid=%')).toEqual({ invalid: undefined });
       expect(parseKeyValue('invalid=%&valid=good')).toEqual({ invalid: undefined, valid: 'good' });
     });
+    it('should parse a string into key-value pairs with duplicates grouped in an array', function() {
+      expect(parseKeyValue('')).toEqual({});
+      expect(parseKeyValue('duplicate=pair')).toEqual({duplicate: 'pair'});
+      expect(parseKeyValue('first=1&first=2')).toEqual({first: ['1','2']});
+      expect(parseKeyValue('escaped%20key=escaped%20value&&escaped%20key=escaped%20value2')).
+      toEqual({'escaped key': ['escaped value','escaped value2']});
+      expect(parseKeyValue('flag1&key=value&flag1')).
+      toEqual({flag1: [true,true], key: 'value'});
+      expect(parseKeyValue('flag1&flag1=value&flag1=value2&flag1')).
+      toEqual({flag1: [true,'value','value2',true]});
+    });
   });
 
   describe('toKeyValue', function() {
-    it('should parse key-value pairs into string', function() {
+    it('should serialize key-value pairs into string', function() {
       expect(toKeyValue({})).toEqual('');
       expect(toKeyValue({simple: 'pair'})).toEqual('simple=pair');
       expect(toKeyValue({first: '1', second: '2'})).toEqual('first=1&second=2');
@@ -330,9 +341,15 @@ describe('angular', function() {
       expect(toKeyValue({emptyKey: ''})).toEqual('emptyKey=');
     });
 
-    it('should parse true values into flags', function() {
+    it('should serialize true values into flags', function() {
       expect(toKeyValue({flag1: true, key: 'value', flag2: true})).toEqual('flag1&key=value&flag2');
     });
+
+    it('should serialize duplicates into duplicate param strings', function() {
+      expect(toKeyValue({key: [323,'value',true]})).toEqual('key=323&key=value&key');
+      expect(toKeyValue({key: [323,'value',true, 1234]})).
+      toEqual('key=323&key=value&key&key=1234');
+  });
   });
 
 

test/ng/locationSpec.js

@@ -368,6 +368,29 @@ describe('$location', function() {
         locationUrl.search('q', '1/2 3');
         expect(locationUrl.search()).toEqual({'q': '1/2 3'});
       });
+
+      it('should return an array for duplicate params', function() {
+        var locationUrl = new LocationHtml5Url('http://host.com');
+        locationUrl.$$parse('http://host.com')
+        locationUrl.search('q', ['1/2 3','4/5 6']);
+        expect(locationUrl.search()).toEqual({'q': ['1/2 3','4/5 6']});
+      });
+
+      it('should encode an array correctly from search and add to url', function() {
+        var locationUrl = new LocationHtml5Url('http://host.com');
+        locationUrl.$$parse('http://host.com')
+        locationUrl.search({'q': ['1/2 3','4/5 6']});
+        expect(locationUrl.absUrl()).toEqual('http://host.com?q=1%2F2%203&q=4%2F5%206');
+      });
+
+      it('should rewrite params when specifing a single param in search', function() {
+        var locationUrl = new LocationHtml5Url('http://host.com');
+        locationUrl.$$parse('http://host.com')
+        locationUrl.search({'q': '1/2 3'});
+        expect(locationUrl.absUrl()).toEqual('http://host.com?q=1%2F2%203');
+        locationUrl.search({'q': '4/5 6'});
+        expect(locationUrl.absUrl()).toEqual('http://host.com?q=4%2F5%206');
+      });
     });
   });