.

src/index.js

@@ -91,7 +91,7 @@ class Tenor {
                 resolve(gifs);
             }).catch(error => {
                 if (error.response.status >= 400 && error.response.status <= 499) {
-                    return reject(new Error('Invalid API Key Provided: ' + this.token));
+                    return reject(new Error(`Invalid API Key Provided: ${this.token}`));
                 }
                 return reject(error);
             });