Add and expose method to test if a language is supported

index.js

@@ -93,3 +93,4 @@ function translate(text, opts) {
 }
 
 module.exports = translate;
+module.exports.languages = languages;

languages.js

@@ -112,4 +112,23 @@ var langs = {
     'zu': 'Zulu'
 };
 
+function isSupported(desiredLang) {
+    desiredLang = desiredLang.toLowerCase();
+
+    if (langs[desiredLang]) {
+        return true;
+    }
+
+    var result = Object.keys(langs).filter(function (key) {
+        if (typeof langs[key] !== 'string') {
+            return false;
+        }
+
+        return langs[key].toLowerCase().indexOf(desiredLang) !== -1;
+    });
+
+    return result.length > 0;
+}
+
 module.exports = langs;
+module.exports.isSupported = isSupported;

test.js

@@ -1,4 +1,6 @@
 import test from 'ava';
+
+import languages from './languages';
 import translate from './index';
 
 test('translate without any options', async t => {
@@ -66,3 +68,23 @@ test('translate some text and get the raw output alongside', async t => {
         t.fail(err.code);
     }
 });
+
+test('get a supported language by code', t => {
+    t.true(languages.isSupported('en'));
+});
+
+test('get an unsupported language by code', t => {
+    t.false(languages.isSupported('js'));
+});
+
+test('get a supported language by name', t => {
+    t.true(languages.isSupported('english'));
+});
+
+test('get an unsupported language by name', t => {
+    t.false(languages.isSupported('javascript'));
+});
+
+test('get a supported language by a part of its name', t => {
+    t.true(languages.isSupported('chinese'));
+});