feat: remove through2 dependency (#770)

* drop: through2 dependency

Author: laljikanjareeya

package.json

@@ -62,8 +62,7 @@
     "long": "^4.0.0",
     "pumpify": "^2.0.0",
     "retry-request": "^4.0.0",
-    "stream-events": "^1.0.2",
-    "through2": "^3.0.0"
+    "stream-events": "^1.0.2"
   },
   "devDependencies": {
     "@types/escape-string-regexp": "^1.0.0",
@@ -75,7 +74,6 @@
     "@types/proxyquire": "^1.3.28",
     "@types/pumpify": "^1.4.1",
     "@types/sinon": "^9.0.0",
-    "@types/through2": "^2.0.34",
     "@types/uuid": "^8.0.0",
     "c8": "^7.1.0",
     "codecov": "^3.6.5",

src/table.ts

@@ -16,14 +16,13 @@ import {promisifyAll} from '@google-cloud/promisify';
 import arrify = require('arrify');
 import {ServiceError} from 'google-gax';
 import {decorateStatus} from './decorateStatus';
-import {PassThrough} from 'stream';
+import {PassThrough, Transform} from 'stream';
 
 // eslint-disable-next-line @typescript-eslint/no-var-requires
 const concat = require('concat-stream');
 import * as is from 'is';
 // eslint-disable-next-line @typescript-eslint/no-var-requires
 const pumpify = require('pumpify');
-import * as through from 'through2';
 
 import {
   Family,
@@ -810,10 +809,8 @@ Please use the format 'prezzy' or '${instance.name}/tables/prezzy'.`);
 
       requestStream!.on('request', () => numRequestsMade++);
 
-      rowStream = pumpify.obj([
-        requestStream,
-        chunkTransformer,
-        through.obj((rowData, enc, next) => {
+      const toRowStream = new Transform({
+        transform: (rowData, _, next) => {
           if (
             chunkTransformer._destroyed ||
             // eslint-disable-next-line @typescript-eslint/no-explicit-any
@@ -826,8 +823,11 @@ Please use the format 'prezzy' or '${instance.name}/tables/prezzy'.`);
           const row = this.row(rowData.key);
           row.data = rowData.data;
           next(null, row);
-        }),
-      ]);
+        },
+        objectMode: true,
+      });
+
+      rowStream = pumpify.obj([requestStream, chunkTransformer, toRowStream]);
 
       rowStream.on('error', (error: ServiceError) => {
         if (IGNORED_STATUS_CODES.has(error.code)) {
@@ -1561,19 +1561,24 @@ Please use the format 'prezzy' or '${instance.name}/tables/prezzy'.`);
       appProfileId: this.bigtable.appProfileId,
     };
 
+    const rowKeysStream = new Transform({
+      transform(key, enc, next) {
+        next(null, {
+          key: key.rowKey,
+          offset: key.offsetBytes,
+        });
+      },
+      objectMode: true,
+    });
+
     return pumpify.obj([
       this.bigtable.request({
         client: 'BigtableClient',
         method: 'sampleRowKeys',
         reqOpts,
         gaxOpts: gaxOptions,
       }),
-      through.obj((key, enc, next) => {
-        next(null, {
-          key: key.rowKey,
-          offset: key.offsetBytes,
-        });
-      }),
+      rowKeysStream,
     ]);
   }
 

system-test/read-rows-acceptance-test.json

@@ -378,14 +378,6 @@
         "name": "invalid - duplicate row key",
         "chunks_base64": ["CgRSS18xEgMKAUEaAwoBQyBkMgl2YWx1ZS1WQUxIAQ==", "CgRSS18xEgMKAUIaAwoBRCBkMgl2YWx1ZS1WQUxIAQ=="],
         "results": [{
-            "fm": "A",
-            "rk": "RK_1",
-            "qual": "C",
-            "label": "",
-            "error": false,
-            "value": "value-VAL",
-            "ts": 100
-        }, {
             "fm": "",
             "rk": "",
             "qual": "",
@@ -399,14 +391,6 @@
         "name": "invalid - new row missing row key",
         "chunks_base64": ["CgRSS18xEgMKAUEaAwoBQyBkMgl2YWx1ZS1WQUxIAQ==", "IGQyCXZhbHVlLVZBTEgB"],
         "results": [{
-            "fm": "A",
-            "rk": "RK_1",
-            "qual": "C",
-            "label": "",
-            "error": false,
-            "value": "value-VAL",
-            "ts": 100
-        }, {
             "fm": "",
             "rk": "",
             "qual": "",