fix: reduce duplicate code (#1612)

* fix: reduce duplicate code

* fix: removed unused dependency

* fix: npm run fix

* apply Dan's suggestion

* add error handling back in

* lint

gax/src/streamingCalls/streaming.ts

@@ -271,11 +271,7 @@ export class StreamProxy extends duplexify implements GRPCCallResult {
    */
   streamHandoffHelper(stream: CancellableStream, retry: RetryOptions): void {
     let enteredError = false;
-    const eventsToForward = ['metadata', 'response', 'status'];
-
-    eventsToForward.forEach(event => {
-      stream.on(event, this.emit.bind(this, event));
-    });
+    this.eventForwardHelper(stream);
 
     stream.on('error', error => {
       enteredError = true;
@@ -296,20 +292,14 @@ export class StreamProxy extends duplexify implements GRPCCallResult {
     });
   }
 
-  /**
-   * Forward events from an API request stream to the user's stream.
-   * @param {Stream} stream - The API request stream.
-   * @param {RetryOptions} retry - Configures the exceptions upon which the
-   *   function should retry, and the parameters to the exponential backoff retry
-   *   algorithm.
-   */
-
-  forwardEvents(stream: Stream) {
+  eventForwardHelper(stream: Stream) {
     const eventsToForward = ['metadata', 'response', 'status'];
     eventsToForward.forEach(event => {
       stream.on(event, this.emit.bind(this, event));
     });
+  }
 
+  statusMetadataHelper(stream: Stream) {
     // gRPC is guaranteed emit the 'status' event but not 'metadata', and 'status' is the last event to emit.
     // Emit the 'response' event if stream has no 'metadata' event.
     // This avoids the stream swallowing the other events, such as 'end'.
@@ -340,6 +330,18 @@ export class StreamProxy extends duplexify implements GRPCCallResult {
       });
       this._responseHasSent = true;
     });
+  }
+  /**
+   * Forward events from an API request stream to the user's stream.
+   * @param {Stream} stream - The API request stream.
+   * @param {RetryOptions} retry - Configures the exceptions upon which the
+   *   function should retry, and the parameters to the exponential backoff retry
+   *   algorithm.
+   */
+  forwardEvents(stream: Stream) {
+    this.eventForwardHelper(stream);
+    this.statusMetadataHelper(stream);
+
     stream.on('error', error => {
       GoogleError.parseGRPCStatusDetails(error);
     });
@@ -368,40 +370,8 @@ export class StreamProxy extends duplexify implements GRPCCallResult {
     retry: RetryOptions
   ): CancellableStream | undefined {
     let retryStream = this.stream;
-    const eventsToForward = ['metadata', 'response', 'status'];
-    eventsToForward.forEach(event => {
-      stream.on(event, this.emit.bind(this, event));
-    });
-    // gRPC is guaranteed emit the 'status' event but not 'metadata', and 'status' is the last event to emit.
-    // Emit the 'response' event if stream has no 'metadata' event.
-    // This avoids the stream swallowing the other events, such as 'end'.
-    stream.on('status', () => {
-      if (!this._responseHasSent) {
-        stream.emit('response', {
-          code: 200,
-          details: '',
-          message: 'OK',
-        });
-      }
-    });
-
-    // We also want to supply the status data as 'response' event to support
-    // the behavior of google-cloud-node expects.
-    // see:
-    // https://github.com/GoogleCloudPlatform/google-cloud-node/pull/1775#issuecomment-259141029
-    // https://github.com/GoogleCloudPlatform/google-cloud-node/blob/116436fa789d8b0f7fc5100b19b424e3ec63e6bf/packages/common/src/grpc-service.js#L355
-    stream.on('metadata', metadata => {
-      // Create a response object with succeeds.
-      // TODO: unify this logic with the decoration of gRPC response when it's
-      // added. see: https://github.com/googleapis/gax-nodejs/issues/65
-      stream.emit('response', {
-        code: 200,
-        details: '',
-        message: 'OK',
-        metadata,
-      });
-      this._responseHasSent = true;
-    });
+    this.eventForwardHelper(stream);
+    this.statusMetadataHelper(stream);
 
     stream.on('error', error => {
       const timeout = retry.backoffSettings.totalTimeoutMillis;

gax/src/streamingRetryRequest.ts

@@ -30,7 +30,7 @@ const requestOps = null;
 const objectMode = true; // we don't support objectMode being false
 
 interface streamingRetryRequestOptions {
-  request?: Function;
+  request: Function;
   maxRetries?: number;
 }
 /**
@@ -40,14 +40,8 @@ interface streamingRetryRequestOptions {
  */
 export function streamingRetryRequest(opts: streamingRetryRequestOptions) {
   opts = Object.assign({}, DEFAULTS, opts);
-
   if (opts.request === undefined) {
-    try {
-      // eslint-disable-next-line node/no-unpublished-require
-      opts.request = require('request');
-    } catch (e) {
-      throw new Error('A request library must be provided to retry-request.');
-    }
+    throw new Error('A request function must be provided');
   }
 
   let numNoResponseAttempts = 0;

gax/test/unit/streamingRetryRequest.ts

@@ -96,14 +96,14 @@ describe('retry-request', () => {
         });
       assert.strictEqual(retryStream._readableState.objectMode, true);
     });
-
     it('throws request error', done => {
       try {
         const opts = {};
+        //@ts-expect-error
         streamingRetryRequest(opts);
       } catch (err) {
         assert(err instanceof Error);
-        assert.match(err.message, /A request library must be provided/);
+        assert.match(err.message, /A request function must be provided/);
         done();
       }
     });