Fix #3: return subtags as usual for redundant tags

README.md

@@ -211,6 +211,14 @@ Returns `grandfathered` if the tag is grandfathered, `redundant` if the tag is r
 
 Returns an array of subtags making up the tag, as `Subtag` objects.
 
+#### tag.language(), tag.region(), tag.script() ####
+
+Shortcuts for `tag.find('language')`, `tag.find('region')` and `tag.find('script')`.
+
+#### tag.find(type) ####
+
+Find a subtag of the given type from those making up the tag.
+
 #### tag.valid() ####
 
 Returns `true` if the tag is valid, `false` otherwise.

lib/Tag.js

@@ -57,8 +57,8 @@ Tag.prototype.preferred = function() {
 Tag.prototype.subtags = function() {
 	var codes, data = this.data, subtags = [];
 
-	// No subtags if the tag is grandfathered or redundant.
-	if (data.record) {
+	// No subtags if the tag is grandfathered.
+	if (data.record && this.type() === 'grandfathered') {
 		return subtags;
 	}
 
@@ -141,6 +141,30 @@ Tag.prototype.subtags = function() {
 	return subtags;
 };
 
+Tag.prototype.language = function() {
+	return this.find('language');
+};
+
+Tag.prototype.region = function() {
+	return this.find('region');
+};
+
+Tag.prototype.script = function() {
+	return this.find('script');
+};
+
+Tag.prototype.find = function(type) {
+	var i, l, subtag, subtags = this.subtags();
+
+	for (i = 0, l = subtags.length; i < l; i++) {
+		subtag = subtags[i];
+
+		if (subtag.type() === type) {
+			return subtag;
+		}
+	}
+};
+
 Tag.prototype.valid = function() {
 	return this.errors().length < 1;
 };

test/lib/TagTest.js

@@ -95,15 +95,19 @@ suite('Tag', function() {
 		assert.equal(tag.type(), 'grandfathered');
 		subtags = tag.subtags();
 		assert.deepEqual(subtags, []);
+		assert.equal(undefined, tag.region());
+		assert.equal(undefined, tag.language());
 	});
 
-	test('tag.subtags() returns empty array for redundant tag', function() {
+	test('tag.subtags() returns array for redundant tag', function() {
 		var tag, subtags;
 
 		tag = new Tag('az-Arab');
 		assert.equal(tag.type(), 'redundant');
 		subtags = tag.subtags();
-		assert.deepEqual(subtags, []);
+		assert.equal(2, subtags.length);
+		assert.equal(subtags[0].format(), 'az');
+		assert.equal(subtags[1].format(), 'Arab');
 	});
 
 	test('tag.errors() returns error for deprecated grandfathered tag', function() {
@@ -487,7 +491,7 @@ suite('Tag', function() {
 		assert.equal(tag.added(), '1998-03-10');
 	});
 
-	test('tag.description() returns description when available', function() {
+	test('tag.descriptions() returns descriptions when available', function() {
 		var tag;
 
 		tag = new Tag('i-default');
@@ -520,4 +524,16 @@ suite('Tag', function() {
 
 		assert.equal(new Tag('zh-Hans').preferred(), null);
 	});
+
+	test('tag.region() and tag.language() return subtags for redundant tags', function() {
+		var tag;
+
+		tag = new Tag('es-419');
+		assert.deepEqual(tag.region().descriptions(), ['Latin America and the Caribbean']);
+		assert.deepEqual(tag.language().descriptions(), ['Spanish', 'Castilian']);
+
+		tag = new Tag('sgn-NL');
+		assert.deepEqual(tag.region().descriptions(), ['Netherlands']);
+		assert.deepEqual(tag.language().descriptions(), ['Sign languages']);
+	});
 });