Remove unnecessary through2 package (#1430)

Summary:
through2 is a legacy dependency and is no longer required. Metro targets Node 18 where Transform streams are stable and do not need a userland package.

Changelog: [Internal] Remove unnecessary through2 package

Pull Request resolved: #1430

Test Plan:
All tests pass on Node 18:

<img width="752" alt="Screenshot 2025-01-21 at 00 38 31" src="https://github.com/user-attachments/assets/4c3179a7-7203-41c9-9ed9-e14d83238048" />

Reviewed By: vzaidman

Differential Revision: D68437314

Pulled By: robhogan

fbshipit-source-id: d70503ad8c5638392b7af883b20a8edd3f7db38b

Author: talentlessguy

packages/metro-symbolicate/package.json

@@ -22,7 +22,6 @@
     "metro-source-map": "0.81.0",
     "nullthrows": "^1.1.1",
     "source-map": "^0.5.6",
-    "through2": "^2.0.1",
     "vlq": "^1.0.0"
   },
   "engines": {

packages/metro-symbolicate/src/symbolicate.js

@@ -23,8 +23,7 @@ const Symbolication = require('./Symbolication.js');
 const fs = require('fs');
 // flowlint-next-line untyped-import:off
 const SourceMapConsumer = require('source-map').SourceMapConsumer;
-// flowlint-next-line untyped-import:off
-const through2 = require('through2');
+const {Transform} = require('stream');
 
 function printHelp() {
   const usages = [
@@ -167,35 +166,34 @@ async function main(
         ),
       );
     } else if (argv[0] === '--attribution') {
-      let buffer = '';
+      let lineBuffer = '';
+
+      const streamToLines: Transform = new Transform({
+        transform(data, _enc, callback) {
+          // Take arbitrary strings, output single lines
+          lineBuffer += data.toString();
+          const lines = lineBuffer.split('\n');
+          for (let i = 0, e = lines.length - 1; i < e; i++) {
+            streamToLines.push(lines[i]);
+          }
+          lineBuffer = lines[lines.length - 1];
+          callback();
+        },
+      });
+
+      const symbolicateLines: Transform = new Transform({
+        transform(data, enc, callback) {
+          // This is JSONL, so each line is a separate JSON object
+          const obj = JSON.parse(data.toString());
+          context.symbolicateAttribution(obj);
+          symbolicateLines.push(JSON.stringify(obj) + '\n');
+          callback();
+        },
+        objectMode: true,
+      });
+
       await waitForStream(
-        stdin
-          .pipe(
-            /* $FlowFixMe[missing-this-annot] The 'this' type annotation(s)
-             * required by Flow's LTI update could not be added via codemod */
-            through2(function (data, enc, callback) {
-              // Take arbitrary strings, output single lines
-              buffer += data;
-              const lines = buffer.split('\n');
-              for (let i = 0, e = lines.length - 1; i < e; i++) {
-                this.push(lines[i]);
-              }
-              buffer = lines[lines.length - 1];
-              callback();
-            }),
-          )
-          .pipe(
-            /* $FlowFixMe[missing-this-annot] The 'this' type annotation(s)
-             * required by Flow's LTI update could not be added via codemod */
-            through2.obj(function (data, enc, callback) {
-              // This is JSONL, so each line is a separate JSON object
-              const obj = JSON.parse(data);
-              context.symbolicateAttribution(obj);
-              this.push(JSON.stringify(obj) + '\n');
-              callback();
-            }),
-          )
-          .pipe(stdout),
+        stdin.pipe(streamToLines).pipe(symbolicateLines).pipe(stdout),
       );
     } else if (argv[0].endsWith('.cpuprofile')) {
       // NOTE: synchronous

yarn.lock

@@ -2230,11 +2230,6 @@ core-js-pure@^3.25.1:
   resolved "https://registry.yarnpkg.com/core-js-pure/-/core-js-pure-3.26.1.tgz#653f4d7130c427820dcecd3168b594e8bb095a33"
   integrity sha512-VVXcDpp/xJ21KdULRq/lXdLzQAtX7+37LzpyfFM973il0tWSsDEoyzG38G14AjTpK9VTfiNM9jnFauq/CpaWGQ==
 
-core-util-is@~1.0.0:
-  version "1.0.2"
-  resolved "https://registry.yarnpkg.com/core-util-is/-/core-util-is-1.0.2.tgz#b5fd54220aa2bc5ab57aab7140c940754503c1a7"
-  integrity sha1-tf1UIgqivFq1eqtxQMlAdUUDwac=
-
 cosmiconfig@^5.0.5:
   version "5.2.1"
   resolved "https://registry.yarnpkg.com/cosmiconfig/-/cosmiconfig-5.2.1.tgz#040f726809c591e77a17c0a3626ca45b4f168b1a"
@@ -3501,11 +3496,6 @@ is-weakref@^1.0.2:
   dependencies:
     call-bind "^1.0.2"
 
-isarray@~1.0.0:
-  version "1.0.0"
-  resolved "https://registry.yarnpkg.com/isarray/-/isarray-1.0.0.tgz#bb935d48582cba168c06834957a54a3e07124f11"
-  integrity sha1-u5NdSFgsuhaMBoNJV6VKPgcSTxE=
-
 isexe@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/isexe/-/isexe-2.0.0.tgz#e8fbf374dc556ff8947a10dcb0572d633f2cfa10"
@@ -4851,11 +4841,6 @@ pretty-format@^29.7.0:
     ansi-styles "^5.0.0"
     react-is "^18.0.0"
 
-process-nextick-args@~2.0.0:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/process-nextick-args/-/process-nextick-args-2.0.1.tgz#7820d9b16120cc55ca9ae7792680ae7dba6d7fe2"
-  integrity sha512-3ouUOpQhtgrbOa17J7+uxOTpITYWaGP7/AhoR3+A+/1e9skrzelGi/dXzEYyvbxubEF6Wn2ypscTKiKJFFn1ag==
-
 progress@^2.0.0:
   version "2.0.3"
   resolved "https://registry.yarnpkg.com/progress/-/progress-2.0.3.tgz#7e8cf8d8f5b8f239c1bc68beb4eb78567d572ef8"
@@ -4938,19 +4923,6 @@ [email protected]:
   resolved "https://registry.yarnpkg.com/react/-/react-19.0.0.tgz#6e1969251b9f108870aa4bff37a0ce9ddfaaabdd"
   integrity sha512-V8AVnmPIICiWpGfm6GLzCR/W5FXLchHop40W4nXBmdlEceh16rCN8O8LNWm5bh5XUX91fh7KpA+W0TgMKmgTpQ==
 
-readable-stream@~2.3.6:
-  version "2.3.7"
-  resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-2.3.7.tgz#1eca1cf711aef814c04f62252a36a62f6cb23b57"
-  integrity sha512-Ebho8K4jIbHAxnuxi7o42OrZgF/ZTNcsZj6nRKyUmkhLFq8CHItp/fy6hQZuZmP/n3yZ9VBUbp4zz/mX8hmYPw==
-  dependencies:
-    core-util-is "~1.0.0"
-    inherits "~2.0.3"
-    isarray "~1.0.0"
-    process-nextick-args "~2.0.0"
-    safe-buffer "~5.1.1"
-    string_decoder "~1.1.1"
-    util-deprecate "~1.0.1"
-
 recast@^0.21.0:
   version "0.21.5"
   resolved "https://registry.yarnpkg.com/recast/-/recast-0.21.5.tgz#e8cd22bb51bcd6130e54f87955d33a2b2e57b495"
@@ -5106,7 +5078,7 @@ run-parallel@^1.1.9:
   dependencies:
     queue-microtask "^1.2.2"
 
-safe-buffer@~5.1.0, safe-buffer@~5.1.1:
+safe-buffer@~5.1.1:
   version "5.1.2"
   resolved "https://registry.yarnpkg.com/safe-buffer/-/safe-buffer-5.1.2.tgz#991ec69d296e0313747d59bdfd2b745c35f8828d"
   integrity sha512-Gd2UZBJDkXlY7GbJxfsE8/nvKkUEU1G38c1siN6QP6a9PT9MmHB8GnpscSmMJSoF8LOIrt8ud/wPtojys4G6+g==
@@ -5347,13 +5319,6 @@ string.prototype.trimstart@^1.0.5:
     define-properties "^1.1.4"
     es-abstract "^1.19.5"
 
-string_decoder@~1.1.1:
-  version "1.1.1"
-  resolved "https://registry.yarnpkg.com/string_decoder/-/string_decoder-1.1.1.tgz#9cf1611ba62685d7030ae9e4ba34149c3af03fc8"
-  integrity sha512-n/ShnvDi6FHbbVfviro+WojiFzv+s8MPMHBczVePfUpDJLwoLT0ht1l4YwBCbi8pJAveEEdnkHyPyTP/mzRfwg==
-  dependencies:
-    safe-buffer "~5.1.0"
-
 strip-ansi@^5.2.0:
   version "5.2.0"
   resolved "https://registry.yarnpkg.com/strip-ansi/-/strip-ansi-5.2.0.tgz#8c9a536feb6afc962bdfa5b104a5091c1ad9c0ae"
@@ -5476,14 +5441,6 @@ throat@^5.0.0:
   resolved "https://registry.yarnpkg.com/throat/-/throat-5.0.0.tgz#c5199235803aad18754a667d659b5e72ce16764b"
   integrity sha512-fcwX4mndzpLQKBS1DVYhGAcYaYt7vsHNIvQV+WXMvnow5cgjPphq5CaayLaGsjRdSCKZFNGt7/GYAuXaNOiYCA==
 
-through2@^2.0.1:
-  version "2.0.5"
-  resolved "https://registry.yarnpkg.com/through2/-/through2-2.0.5.tgz#01c1e39eb31d07cb7d03a96a70823260b23132cd"
-  integrity sha512-/mrRod8xqpA+IHSLyGCQ2s8SPHiCDEeQJSep1jqLYeEUClOFG2Qsh+4FU6G9VeqpZnGW/Su8LQGc4YKni5rYSQ==
-  dependencies:
-    readable-stream "~2.3.6"
-    xtend "~4.0.1"
-
 "through@>=2.2.7 <3":
   version "2.3.8"
   resolved "https://registry.yarnpkg.com/through/-/through-2.3.8.tgz#0dd4c9ffaabc357960b1b724115d7e0e86a2e1f5"
@@ -5634,11 +5591,6 @@ uri-js@^4.2.2:
   dependencies:
     punycode "^2.1.0"
 
-util-deprecate@~1.0.1:
-  version "1.0.2"
-  resolved "https://registry.yarnpkg.com/util-deprecate/-/util-deprecate-1.0.2.tgz#450d4dc9fa70de732762fbd2d4a28981419a0ccf"
-  integrity sha1-RQ1Nyfpw3nMnYvvS1KKJgUGaDM8=
-
 [email protected]:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/utils-merge/-/utils-merge-1.0.1.tgz#9f95710f50a267947b2ccc124741c1028427e713"
@@ -5736,11 +5688,6 @@ xml@^1.0.1:
   resolved "https://registry.yarnpkg.com/xml/-/xml-1.0.1.tgz#78ba72020029c5bc87b8a81a3cfcd74b4a2fc1e5"
   integrity sha512-huCv9IH9Tcf95zuYCsQraZtWnJvBtLVE0QHMOs8bWyZAFZNDcYjsPq1nEx8jKA9y+Beo9v+7OBPRisQTjinQMw==
 
-xtend@~4.0.1:
-  version "4.0.2"
-  resolved "https://registry.yarnpkg.com/xtend/-/xtend-4.0.2.tgz#bb72779f5fa465186b1f438f674fa347fdb5db54"
-  integrity sha512-LKYU1iAXJXUgAXn9URjiu+MWhyUXHsvfp7mcuYm9dSUKK0/CjtrUwFAxD82/mCWbtLsGjFIad0wIsod4zrTAEQ==
-
 y18n@^5.0.5:
   version "5.0.8"
   resolved "https://registry.yarnpkg.com/y18n/-/y18n-5.0.8.tgz#7f4934d0f7ca8c56f95314939ddcd2dd91ce1d55"