Added lingo.join()

Readme.md

@@ -75,6 +75,18 @@ Camelcase with first character upppercase:
     lingo.camelcase('foo bar baz', true);
     // => "FooBarBaz"
 
+## lingo.join()
+
+Defaults to "and":
+
+    lingo.join(['fruits', 'veggies', 'sugar']);
+    // => "fruits, veggies and sugar"
+
+Supplying "or":
+
+    lingo.join(['fruits', 'veggies', 'sugar'], 'or');
+    // => "fruits, veggies or sugar"
+
 ## i18n (translations)
 
 New languages can be defined as shown below:

lib/lingo.js

@@ -90,3 +90,30 @@ exports.camelcase = function(str, uppercaseFirst){
     return word;
   }).join('');
 };
+
+/**
+ * Join an array with the given `last` string
+ * which defaults to "and".
+ *
+ * Examples:
+ *
+ *    lingo.join(['fruits', 'veggies', 'sugar']);
+ *    // => "fruits, veggies and sugar"
+ *
+ *    lingo.join(['fruits', 'veggies', 'sugar'], 'or');
+ *    // => "fruits, veggies or sugar"
+ *
+ * @param {Array} arr
+ * @param {String} last
+ * @return {String}
+ * @api public
+ */
+
+exports.join = function(arr, last){
+  var str = arr.pop()
+    , last = last || 'and';
+  if (arr.length) {
+    str = arr.join(', ') + ' ' + last + ' ' + str;
+  }
+  return str;
+};

test/lingo.test.js

@@ -23,6 +23,13 @@ module.exports = {
     assert.equal('UserRole', lingo.camelcase('user role', true));
   },
 
+  'test .join()': function(assert){
+    assert.equal('foo', lingo.join(['foo']));
+    assert.equal('foo and bar', lingo.join(['foo', 'bar']));
+    assert.equal('foo, bar and baz', lingo.join(['foo', 'bar', 'baz']));
+    assert.equal('foo, bar or baz', lingo.join(['foo', 'bar', 'baz'], 'or'));
+  },
+
   'test Language mapping': function(assert){
     assert.equal('en', lingo.Language.en.code);
   }