React Native Windows Blob memory leak sample

ReactNative/fetchwinleak/.bundle/config

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+BUNDLE_PATH: "vendor/bundle"
+BUNDLE_FORCE_RUBY_PLATFORM: 1

ReactNative/fetchwinleak/.eslintrc.js

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+module.exports = {
+  root: true,
+  extends: '@react-native',
+};

ReactNative/fetchwinleak/.gitignore

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+# OSX
+#
+.DS_Store
+
+# Xcode
+#
+build/
+*.pbxuser
+!default.pbxuser
+*.mode1v3
+!default.mode1v3
+*.mode2v3
+!default.mode2v3
+*.perspectivev3
+!default.perspectivev3
+xcuserdata
+*.xccheckout
+*.moved-aside
+DerivedData
+*.hmap
+*.ipa
+*.xcuserstate
+ios/.xcode.env.local
+macos/.xcode.env.local
+
+# Android/IntelliJ
+#
+build/
+.idea
+.gradle
+local.properties
+*.iml
+*.hprof
+.cxx/
+*.keystore
+!debug.keystore
+
+# node.js
+#
+node_modules/
+npm-debug.log
+yarn-error.log
+
+# fastlane
+#
+# It is recommended to not store the screenshots in the git repo. Instead, use fastlane to re-generate the
+# screenshots whenever they are needed.
+# For more information about the recommended setup visit:
+# https://docs.fastlane.tools/best-practices/source-control/
+
+**/fastlane/report.xml
+**/fastlane/Preview.html
+**/fastlane/screenshots
+**/fastlane/test_output
+
+# Bundle artifact
+*.jsbundle
+
+# Ruby / CocoaPods
+/ios/Pods/
+/vendor/bundle/
+
+# Temporary files created by Metro to check the health of the file watcher
+.metro-health-check*
+
+# testing
+/coverage
+
+# Visual Studio
+.vscode/

ReactNative/fetchwinleak/.prettierrc.js

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+module.exports = {
+  arrowParens: 'avoid',
+  bracketSameLine: true,
+  bracketSpacing: false,
+  singleQuote: true,
+  trailingComma: 'all',
+};

ReactNative/fetchwinleak/.watchmanconfig

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+{}

ReactNative/fetchwinleak/App.tsx

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+/**
+ * Sample React Native App
+ * https://github.com/facebook/react-native
+ *
+ * @see https://retool.com/blog/the-react-lifecycle-methods-and-hooks-explained
+ * @format
+ */
+
+import React, {useState} from 'react';
+import {Button, StyleSheet, Text, TextInput, View} from 'react-native';
+
+const App = () => {
+	const [total, setTotal] = useState(0);
+	const [reqId, setReqId] = useState(0);
+	const [size, setSize] = useState(`${8 * 1024 * 1024}`);
+	const uri = `http://localhost:5000/${size}`;
+
+	const doFetch = async () => {
+		var response = await fetch(uri);
+		var text = await response.text();
+		setReqId(reqId + 1);
+		setTotal(total + text.length);
+	};
+
+	return (
+		<View
+			style={{
+				flex: 1,
+				justifyContent: 'center',
+			}}>
+			<Button onPress={doFetch} title="Reload" />
+			<TextInput style={styles.input} onChangeText={setSize} value={size} />
+			<Text></Text>
+			<Text style={styles.text}>Responses: {reqId}</Text>
+			<Text style={styles.text}>[{total}]</Text>
+		</View>
+	);
+};
+
+const styles = StyleSheet.create({
+	text: {
+		textAlign: 'center',
+	},
+	input: {
+		textAlign: 'center',
+		color: 'white',
+		backgroundColor: '#003269',
+		fontWeight: 'bold',
+	},
+});
+
+export default App;

ReactNative/fetchwinleak/Gemfile

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+source 'https://rubygems.org'
+
+# You may use http://rbenv.org/ or https://rvm.io/ to install and use this version
+ruby ">= 2.6.10"
+
+gem 'cocoapods', '~> 1.12'

ReactNative/fetchwinleak/Gemfile.lock

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+GEM
+  remote: https://rubygems.org/
+  specs:
+    CFPropertyList (3.0.6)
+      rexml
+    activesupport (6.1.7.4)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 1.6, < 2)
+      minitest (>= 5.1)
+      tzinfo (~> 2.0)
+      zeitwerk (~> 2.3)
+    addressable (2.8.4)
+      public_suffix (>= 2.0.2, < 6.0)
+    algoliasearch (1.27.5)
+      httpclient (~> 2.8, >= 2.8.3)
+      json (>= 1.5.1)
+    atomos (0.1.3)
+    claide (1.1.0)
+    cocoapods (1.12.1)
+      addressable (~> 2.8)
+      claide (>= 1.0.2, < 2.0)
+      cocoapods-core (= 1.12.1)
+      cocoapods-deintegrate (>= 1.0.3, < 2.0)
+      cocoapods-downloader (>= 1.6.0, < 2.0)
+      cocoapods-plugins (>= 1.0.0, < 2.0)
+      cocoapods-search (>= 1.0.0, < 2.0)
+      cocoapods-trunk (>= 1.6.0, < 2.0)
+      cocoapods-try (>= 1.1.0, < 2.0)
+      colored2 (~> 3.1)
+      escape (~> 0.0.4)
+      fourflusher (>= 2.3.0, < 3.0)
+      gh_inspector (~> 1.0)
+      molinillo (~> 0.8.0)
+      nap (~> 1.0)
+      ruby-macho (>= 2.3.0, < 3.0)
+      xcodeproj (>= 1.21.0, < 2.0)
+    cocoapods-core (1.12.1)
+      activesupport (>= 5.0, < 8)
+      addressable (~> 2.8)
+      algoliasearch (~> 1.0)
+      concurrent-ruby (~> 1.1)
+      fuzzy_match (~> 2.0.4)
+      nap (~> 1.0)
+      netrc (~> 0.11)
+      public_suffix (~> 4.0)
+      typhoeus (~> 1.0)
+    cocoapods-deintegrate (1.0.5)
+    cocoapods-downloader (1.6.3)
+    cocoapods-plugins (1.0.0)
+      nap
+    cocoapods-search (1.0.1)
+    cocoapods-trunk (1.6.0)
+      nap (>= 0.8, < 2.0)
+      netrc (~> 0.11)
+    cocoapods-try (1.2.0)
+    colored2 (3.1.2)
+    concurrent-ruby (1.2.2)
+    escape (0.0.4)
+    ethon (0.16.0)
+      ffi (>= 1.15.0)
+    ffi (1.15.5)
+    fourflusher (2.3.1)
+    fuzzy_match (2.0.4)
+    gh_inspector (1.1.3)
+    httpclient (2.8.3)
+    i18n (1.14.1)
+      concurrent-ruby (~> 1.0)
+    json (2.6.3)
+    minitest (5.18.1)
+    molinillo (0.8.0)
+    nanaimo (0.3.0)
+    nap (1.1.0)
+    netrc (0.11.0)
+    public_suffix (4.0.7)
+    rexml (3.2.5)
+    ruby-macho (2.5.1)
+    typhoeus (1.4.0)
+      ethon (>= 0.9.0)
+    tzinfo (2.0.6)
+      concurrent-ruby (~> 1.0)
+    xcodeproj (1.22.0)
+      CFPropertyList (>= 2.3.3, < 4.0)
+      atomos (~> 0.1.3)
+      claide (>= 1.0.2, < 2.0)
+      colored2 (~> 3.1)
+      nanaimo (~> 0.3.0)
+      rexml (~> 3.2.4)
+    zeitwerk (2.6.8)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  cocoapods (~> 1.12)
+
+RUBY VERSION
+   ruby 2.6.10p210
+
+BUNDLED WITH
+   1.17.2

ReactNative/fetchwinleak/README.md

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+# `Memory leak with continuous Blob usage:`
+
+This sample showcases the memory leak fixed for iOS, macOS [#24745](https://github.com/facebook/react-native/pull/24745), on Windows.
+
+React Native does not trigger any clean-up mechanism when a JabaScritp `Blob` instance goes out of scope and is garbage-collected.
+The associated blob data on the native side stays in memory, leading to memory leaks as subsiquent Blob objects are created/disposed.
+
+This sample app provides the following:
+- A React Native Windows app that makes `fetch` requests to an HTTP endpoint for an arbitrary number of bytes.
+- A .NET HTTP listener (server) that responds to GET requests with a string of size given by the request URL path:
+  ```
+  http://localhost:5000/{response_content_length}
+  ```
+- A React Native macOS projection of the app for control/reference.
+
+## Environment
+
+- `react-native-windows` version `0.72.15` and earlier
+
+## Instructions
+
+1. Start the client and server
+    ```pwsh
+    yarn
+    npx react-native start-windows
+
+    cd windows\HttpList
+    dotnet run
+    ```
+1. Continuously click on `Reload`.\
+  Use a process monitoring tool to observe the significant increase in memory usage by the application which never goes down.
+
+Note, the macOS variant of this app does not show memory usage issues.

ReactNative/fetchwinleak/__tests__/App.test.tsx

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+/**
+ * @format
+ */
+
+import 'react-native';
+import React from 'react';
+import App from '../App';
+
+// Note: import explicitly to use the types shiped with jest.
+import {it} from '@jest/globals';
+
+// Note: test renderer must be required after react-native.
+import renderer from 'react-test-renderer';
+
+it('renders correctly', () => {
+  renderer.create(<App />);
+});