chore!: clean up the Transporter interface.

src/transporters.ts

@@ -28,11 +28,6 @@ const PRODUCT_NAME = 'google-api-nodejs-client';
 
 export interface Transporter {
   request<T>(opts: GaxiosOptions): GaxiosPromise<T>;
-  request<T>(opts: GaxiosOptions, callback?: BodyResponseCallback<T>): void;
-  request<T>(
-    opts: GaxiosOptions,
-    callback?: BodyResponseCallback<T>
-  ): GaxiosPromise | void;
 }
 
 export interface BodyResponseCallback<T> {
@@ -82,38 +77,14 @@ export class DefaultTransporter implements Transporter {
    * @param callback optional callback that contains GaxiosResponse object.
    * @return GaxiosPromise, assuming no callback is passed.
    */
-  request<T>(opts: GaxiosOptions): GaxiosPromise<T>;
-  request<T>(opts: GaxiosOptions, callback?: BodyResponseCallback<T>): void;
-  request<T>(
-    opts: GaxiosOptions,
-    callback?: BodyResponseCallback<T>
-  ): GaxiosPromise | void {
+  request<T>(opts: GaxiosOptions): GaxiosPromise<T> {
     // ensure the user isn't passing in request-style options
     opts = this.configure(opts);
-    try {
-      validate(opts);
-    } catch (e) {
-      if (callback) {
-        return callback(e as Error);
-      } else {
-        throw e;
-      }
-    }
+    validate(opts);
 
-    if (callback) {
-      request<T>(opts).then(
-        r => {
-          callback(null, r);
-        },
-        e => {
-          callback(this.processError(e));
-        }
-      );
-    } else {
-      return request<T>(opts).catch(e => {
-        throw this.processError(e);
-      });
-    }
+    return request<T>(opts).catch(e => {
+      throw this.processError(e);
+    });
   }
 
   /**

test/test.transporters.ts

@@ -89,35 +89,33 @@
     const scope = nock(url)
       .get('/')
       .reply(400, {error: {code: 500, errors: [firstError, secondError]}});
-    transporter.request({url}, error => {
-      scope.done();
-      assert.strictEqual(error!.message, 'Error 1\nError 2');
-      assert.strictEqual((error as RequestError).code, 500);
-      assert.strictEqual((error as RequestError).errors.length, 2);
-      done();
-    });
+    transporter.request({url}).then(
+      () => {
+        scope.done();
+        done('Unexpected promise success');
+      },
+      error => {
+        scope.done();
+        assert.strictEqual(error!.message, 'Error 1\nError 2');
+        assert.strictEqual((error as RequestError).code, 500);
+        assert.strictEqual((error as RequestError).errors.length, 2);
+        done();
+      }
+    );
   });
 
   it('should return an error for a 404 response', done => {
     const url = 'http://example.com';
     const scope = nock(url).get('/').reply(404, 'Not found');
-    transporter.request({url}, error => {
-      scope.done();
-      assert.strictEqual(error!.message, 'Not found');
-      assert.strictEqual((error as RequestError).code, '404');
-      done();
-    });
-  });
-
-  it('should return an error if you try to use request config options', done => {
-    const expected =
-      "'uri' is not a valid configuration option. Please use 'url' instead. This library is using Axios for requests. Please see https://github.com/axios/axios to learn more about the valid request options.";
-    transporter.request(
-      {
-        uri: 'http://example.com/api',
-      } as GaxiosOptions,
+    transporter.request({url}).then(
+      () => {
+        scope.done();
+        done('Unexpected promise success');
+      },
       error => {
-        assert.strictEqual(error!.message, expected);
+        scope.done();
+        assert.strictEqual(error!.message, 'Not found');
+        assert.strictEqual((error as RequestError).code, '404');
         done();
       }
     );
@@ -151,12 +149,17 @@
   it('should work with a callback', done => {
     const url = 'http://example.com';
     const scope = nock(url).get('/').reply(200);
-    transporter.request({url}, (err, res) => {
-      scope.done();
-      assert.strictEqual(err, null);
-      assert.strictEqual(res!.status, 200);
-      done();
-    });
+    transporter.request({url}).then(
+      res => {
+        scope.done();
+        assert.strictEqual(res!.status, 200);
+        done();
+      },
+      _error => {
+        scope.done();
+        done('Unexpected promise failure');
+      }
+    );
   });
 
   // tslint:disable-next-line ban