Add support for custom pluralize function.

README.md

@@ -23,6 +23,7 @@ var messages = {
 
 var options = {
     debug: true, //[Boolean]: Logs missing translations to console. Defaults to false.
+    pluralize: function(n,translKey){ return n; }  //[Function(count,translationKey)]: Provides a custom pluralization mapping function.
 };
 
 var t = translate(messages, [options]);
@@ -105,3 +106,27 @@ t('hits', 99) => '99 Hits'
 t('date', 2, {day: '13', year: 2014}) => '13. February 2014'
 
 ```
+
+### Custom pluralization
+
+You can also do customized pluralization like this:
+
+```js
+var messages_IS = {
+    sheep: {
+        0: 'Engar kindur',
+        1: '{n} kind',
+        2: '{n} kindur'
+    }
+};
+var pluralize_IS = function ( n, tarnslationKey ) {
+    // Icelandic rules: Numbers ending in 1 are singular - unless ending in 11.
+    return n===0 ? 0 : (n%10 !== 1 || n%100 === 11) ? 2 : 1;
+};
+var t = translate( messages_IS, { pluralize:pluralize_IS });
+
+t('sheep', 0) => 'Engar kindur'
+t('sheep', 1) => '1 kind'
+t('sheep', 2) => '2 kindur'
+t('sheep', 21) => '21 kind'
+```

index.js

@@ -10,14 +10,15 @@
  *    translationKey: 'value123'
  *  }
  * }
- * 
+ *
  * var options = {
  *   debug: true, //[Boolean]: Logs missing translations to console. Defaults to false.
  *   namespaceSplitter: '::' //[String|RegExp]: You can customize the part which splits namespace and translationKeys. Defaults to '::'.
+ *   pluralize: function(n,translKey){ return n; } //[Function(count,translationKey)]: Provides a custom pluralization mapping function.
  * }
- * 
+ *
  * var t = libTranslate.getTranslationFunction(messages, [options])
- * 
+ *
  * t('translationKey')
  * t('translationKey', count)
  * t('translationKey', {replaceKey: 'replacevalue'})
@@ -56,7 +57,7 @@ module.exports = function(messageObject, options) {
     }
 
     //@todo make this more robust. maybe support more levels?
-    var components = translationKey.split(namespaceSplitter); 
+    var components = translationKey.split(namespaceSplitter);
     var namespace = components[0];
     var key = components[1];
 
@@ -73,9 +74,11 @@ module.exports = function(messageObject, options) {
         debug && console.log('[Translation] No plural forms found.');
         return null;
       }
-
-      if(translation[count]){
-        translation = translation[count];
+      var mappedCount = options.pluralize ?
+                            options.pluralize( count, translation ):
+                            count;
+      if(translation[mappedCount]){
+        translation = translation[mappedCount];
       } else if(translation.n) {
         translation = translation.n;
       } else {

test.js

@@ -12,6 +12,11 @@ describe("translate.js", function() {
             3: '{n} Hitses', //some slavic langs have multiple plural forms
             n: '{n} Hits'
         },
+        icelandicSheep: {
+            0: 'Engar kindur',
+            1: '{n} kind', // some languages use singular for any number that ends with 1 (i.e. 101, 21, 31, 51)
+            2: '{n} kindur'
+        },
         date: {
             1: '{day}. January {year}',
             2: '{day}. February {year}',
@@ -40,6 +45,11 @@ describe("translate.js", function() {
 	            3: '{n} Hitses', //some slavic langs have multiple plural forms
 	            n: '{n} Hits'
 	        },
+	        icelandicSheep: {
+	            0: 'Engar kindur',
+	            1: '{n} kind', // some languages use singular for any number that ends with 1 (i.e. 101, 21, 31, 51)
+	            2: '{n} kindur'
+	        },
 	        date: {
 	            1: '{day}. January {year}',
 	            2: '{day}. February {year}',
@@ -184,6 +194,35 @@ describe("translate.js", function() {
 		expect(t3('namespaceA.date', 2, {day: '13', year: 2014})).to.equal('13. February 2014');
 	});
 
+	// custom isPlural function
+	var pluralize_IS = function ( n, tarnslationKey ) {
+    // Icelandic rules: Numbers ending in 1 are singular - unless ending in 11.
+		return n===0 ? 0 : (n%10 !== 1 || n%100 === 11) ? 2 : 1;
+	};
+	var t5 = translate(translationsObject, { pluralize: pluralize_IS });
+	['','namespaceA::'].forEach(function (ns) {
+			var nsTitle = ns ? ' [namespace support]' : '';
+
+			it('should pluralize (0) correctly in Icelandic'+nsTitle, function () {
+				expect(t5(ns+'icelandicSheep', 0)).to.equal('Engar kindur');
+			});
+			it('should pluralize (1) correctly in Icelandic'+nsTitle, function () {
+				expect(t5(ns+'icelandicSheep', 1)).to.equal('1 kind');
+			});
+			it('should pluralize (2) correctly in Icelandic'+nsTitle, function () {
+				expect(t5(ns+'icelandicSheep', 2)).to.equal('2 kindur');
+			});
+			it('should pluralize (11) correctly in Icelandic'+nsTitle, function () {
+				expect(t5(ns+'icelandicSheep', 11)).to.equal('11 kindur');
+			});
+			it('should pluralize (21) correctly in Icelandic'+nsTitle, function () {
+				expect(t5(ns+'icelandicSheep', 21)).to.equal('21 kind');
+			});
+			it('should pluralize (29) correctly in Icelandic'+nsTitle, function () {
+				expect(t5(ns+'icelandicSheep', 29)).to.equal('29 kindur');
+			});
+		})
+
 	//wrong arguments
 	var t4 = translate(translationsObject, 'asd');
 	it("should return a translated string with the correct plural form and replaced placeholders: t(key, count, replacements) [namespace support + wrong options arg]", function() {