Merge pull request #1635 from raccoonback/check-nullable-args-in-tran…

…slator-exist

change to return false when a nullable argument is passed

src/Translator.js

@@ -39,6 +39,10 @@ class Translator extends EventEmitter {
   }
 
   exists(key, options = { interpolation: {} }) {
+    if (key === undefined || key === null) {
+      return false;
+    }
+
     const resolved = this.resolve(key, options);
     return resolved && resolved.res !== undefined;
   }

test/translator/translator.exists.spec.js

@@ -62,5 +62,13 @@ describe('Translator', () => {
         expect(t.exists.apply(t, test.args)).to.eql(test.expected);
       });
     });
+
+    const nullishArgs = ['', undefined, null];
+
+    nullishArgs.forEach(nullishArg => {
+      it(`should return false if a "${nullishArg}" key is passed as an argument`, () => {
+        expect(t.exists(nullishArg)).to.false;
+      });
+    });
   });
 });