fix: Fix invalid literals when only language as options is passed

Author: rubensworks

src/N3DataFactory.js

@@ -376,7 +376,7 @@ function literal(value, languageOrDataType) {
 
   // Create a language-tagged string with base direction
   if (languageOrDataType !== undefined && !('termType' in languageOrDataType)) {
-    return new Literal(`"${value}"@${languageOrDataType.language.toLowerCase()}--${languageOrDataType.direction.toLowerCase()}`);
+    return new Literal(`"${value}"@${languageOrDataType.language.toLowerCase()}${languageOrDataType.direction ? `--${languageOrDataType.direction.toLowerCase()}` : ''}`);
   }
 
   // Automatically determine datatype for booleans and numbers

test/N3DataFactory-test.js

@@ -52,6 +52,10 @@ describe('DataFactory', () => {
       expect(DataFactory.literal('abc', 'en-GB')).toEqual(new Literal('"abc"@en-gb'));
     });
 
+    it('converts a non-empty string with a language via options', () => {
+      expect(DataFactory.literal('abc', { language: 'en-GB' })).toEqual(new Literal('"abc"@en-gb'));
+    });
+
     it('converts a non-empty string with a language and direction', () => {
       expect(DataFactory.literal('abc', { language: 'en-GB', direction: 'rtl' })).toEqual(new Literal('"abc"@en-gb--rtl'));
     });