https://github.com/googleapis/nodejs-bigquery/issues/640

diff.diff

diff --git a/src/table.ts b/src/table.ts
index cbe2d59..e900829 100644
--- a/src/table.ts
+++ b/src/table.ts
@@ -1102,20 +1102,16 @@ class Table extends common.ServiceObject {
     this.bigQuery.createJob(body, callback!);
   }
 
-  createLoadJob(source: string, metadata?: JobLoadMetadata): Writable;
-  createLoadJob(source: File, metadata?: JobLoadMetadata): Promise<JobResponse>;
   createLoadJob(
-    source: string,
-    metadata: JobLoadMetadata,
-    callback: JobCallback
-  ): Writable;
+    source: string | File,
+    metadata?: JobLoadMetadata
+  ): Promise<JobResponse>;
   createLoadJob(
-    source: File,
+    source: string | File,
     metadata: JobLoadMetadata,
     callback: JobCallback
   ): void;
-  createLoadJob(source: string, callback: JobCallback): Writable;
-  createLoadJob(source: File, callback: JobCallback): void;
+  createLoadJob(source: string | File, callback: JobCallback): void;
   /**
    * Load data from a local file or Storage {@link
    * https://cloud.google.com/nodejs/docs/reference/storage/latest/File File}.
@@ -1206,7 +1202,7 @@ class Table extends common.ServiceObject {
     source: string | File,
     metadataOrCallback?: JobLoadMetadata | JobCallback,
     cb?: JobCallback
-  ): void | Promise<JobResponse> | Writable {
+  ): void | Promise<JobResponse> {
     const metadata =
       typeof metadataOrCallback === 'object' ? metadataOrCallback : {};
     const callback =
@@ -1238,13 +1234,13 @@ class Table extends common.ServiceObject {
       }
 
       // Read the file into a new write stream.
-      return fs
-        .createReadStream(source)
+      fs.createReadStream(source)
         .pipe(this.createWriteStream_(metadata))
         .on('error', callback)
         .on('job', job => {
           callback(null, job, job.metadata);
         });
+      return;
     }
 
     // tslint:disable-next-line no-any