fix: load job to a different project ID (#748)

* fix: load job to a different project ID
Co-authored-by: Benjamin E. Coe <bencoe@google.com>

Author: laljikanjareeya

src/table.ts

@@ -1373,13 +1373,17 @@ class Table extends common.ServiceObject {
       metadata.schema = Table.createSchemaFromString_(metadata.schema);
     }
 
-    extend(true, metadata, {
-      destinationTable: {
-        projectId: this.bigQuery.projectId,
-        datasetId: this.dataset.id,
-        tableId: this.id,
+    metadata = extend(
+      true,
+      {
+        destinationTable: {
+          projectId: this.bigQuery.projectId,
+          datasetId: this.dataset.id,
+          tableId: this.id,
+        },
       },
-    });
+      metadata
+    );
 
     let jobId = metadata.jobId || uuid.v4();
 

test/table.ts

@@ -1507,6 +1507,36 @@ describe('BigQuery/Table', () => {
       table.createWriteStream_({schema: SCHEMA_STRING}).emit('writing');
     });
 
+    it('should override destination table', done => {
+      const expectedMetadata = {
+        destinationTable: {
+          projectId: 'projectId-override',
+          datasetId: 'datasetId-override',
+          tableId: 'tableId-override',
+        },
+      };
+      makeWritableStreamOverride = (
+        stream: stream.Stream,
+        options: MakeWritableStreamOptions
+      ) => {
+        assert.deepStrictEqual(
+          options.metadata.configuration?.load?.destinationTable,
+          expectedMetadata.destinationTable
+        );
+        done();
+      };
+
+      table
+        .createWriteStream_({
+          destinationTable: {
+            projectId: 'projectId-override',
+            datasetId: 'datasetId-override',
+            tableId: 'tableId-override',
+          },
+        })
+        .emit('writing');
+    });
+
     it('should return a stream', () => {
       assert(table.createWriteStream_() instanceof stream.Stream);
     });