Support Dart v2.19 for NodeRandom

Author: dipu-bd

.gitignore

@@ -4,6 +4,7 @@
 .packages
 
 # Conventional directory for outputs.
+dart-*/
 build/
 doc/
 coverage/

.pubignore

@@ -5,3 +5,4 @@
 /build
 /scripts
 /.github
+/dart-*

CHANGELOG.md

@@ -1,15 +1,15 @@
 # 2.3.0
 
 - generator_vm.dart
-  - Avoid mixing predictable datetime output with CSPRNG output.
+  - Avoids mixing predictable datetime output with CSPRNG output.
 - generator_js.dart
-  - Avoid mixing predictable datetime output with CSPRNG output.
-  - Added `NodeRandom` as an implementation of `Random` for NodeJS.
-  - `nextInt(max)` draws 32-bit values from Node crypto, supports max ∈ [1, 2^32].
-  - `secureRandom()` uses `Random.secure()` for web browsers, and `NodeRandom` for Node.js.
+  - Avoids mixing predictable datetime output with CSPRNG output.
+  - Adds `NodeRandom` as an implementation of `Random` for NodeJS.
+    - `nextInt(max)` draws 32-bit values from NodeJS's internal `crypto` package.
+  - `secureRandom()` uses `NodeRandom` for secure random numbers.
   - `$generateSeed()` delegates to `secureRandom()`.
 - generators.dart
-  - Fixed spelling of `_hashGenerator`
+  - Fixes spelling of `_hashGenerator`
 
 # 2.2.0
 

lib/src/random/generator_js.dart

@@ -1,54 +1,22 @@
-// Copyright (c) 2024, Sudipto Chandra
+// Copyright (c) 2025, Sudipto Chandra
 // All rights reserved. Check LICENSE file for details.
 
 import 'dart:math' show Random;
-import 'dart:js_interop';
 
-const int _mask32 = 0xFFFFFFFF;
-
-const bool isDart2JS = bool.fromEnvironment('dart.tool.dart2js');
-
-@JS()
-@staticInterop
-class Process {}
-
-@JS()
-@staticInterop
-class Versions {}
-
-@JS('process')
-external Process? get _process;
-
-extension on Process {
-  external Versions? get versions;
-}
+import 'generator_js_legacy.dart'
+    if (dart.library.js_interop) 'generator_js_interop.dart';
 
-extension on Versions {
-  external JSAny get node;
-}
-
-bool get isNodeDart2JS => _process?.versions?.node != null && isDart2JS;
-
-@JS()
-@staticInterop
-class Crypto {}
-
-extension on Crypto {
-  external int randomInt(final int max);
-}
-
-@JS()
-external Crypto require(final String id);
+const int _mask32 = 0xFFFFFFFF;
 
 /// For Node.js environment + dart2js compiler
-class NodeRandom implements Random {
+class NodeRandom extends CryptoRandom implements Random {
   @override
   int nextInt(final int max) {
     if (max < 1 || max > _mask32 + 1) {
       throw RangeError.range(
           max, 1, _mask32 + 1, 'max', 'max must be <= (1 << 32)');
     }
-    return require('crypto').randomInt(max);
+    return cryptoRandomInt(max);
   }
 
   @override
@@ -64,7 +32,7 @@ class NodeRandom implements Random {
 }
 
 /// Returns a secure random generator in JS runtime
-Random secureRandom() => isNodeDart2JS ? NodeRandom() : Random.secure();
+Random secureRandom() => NodeRandom();
 
 /// Generates a random seed
 int $generateSeed() => secureRandom().nextInt(_mask32);

lib/src/random/generator_js_interop.dart

@@ -0,0 +1,33 @@
+// Copyright (c) 2025, Sudipto Chandra
+// All rights reserved. Check LICENSE file for details.
+
+import 'dart:js_interop';
+
+@JS()
+@staticInterop
+class Process {}
+
+@JS()
+@staticInterop
+class Versions {}
+
+@JS()
+@staticInterop
+class Crypto {}
+
+extension on Crypto {
+  external int randomInt(final int max);
+}
+
+@JS('require')
+external Crypto require(final String id);
+
+/// For Node.js environment + dart2js compiler
+abstract class CryptoRandom {
+  Crypto? _crypto;
+
+  int cryptoRandomInt(final int max) {
+    _crypto ??= require('crypto');
+    return _crypto!.randomInt(max);
+  }
+}

lib/src/random/generator_js_legacy.dart

@@ -0,0 +1,29 @@
+// Copyright (c) 2025, Sudipto Chandra
+// All rights reserved. Check LICENSE file for details.
+
+// Dart v2.19 compatible version
+// Works with dart2js in a Node.js runtime (where `require` exists).
+
+// ignore_for_file: deprecated_member_use, depend_on_referenced_packages
+
+import 'dart:js' as js;
+
+js.JsObject _require(String id) {
+  final r = js.context['require'];
+  if (r == null) {
+    throw StateError("`require` is not available.");
+  }
+  return (r as js.JsFunction).apply([id]) as js.JsObject;
+}
+
+/// For Node.js environment + dart2js compiler
+abstract class CryptoRandom {
+  js.JsObject? _crypto;
+  js.JsFunction? _randomInt;
+
+  int cryptoRandomInt(final int max) {
+    _crypto ??= _require('crypto');
+    _randomInt ??= _crypto!['randomInt'] as js.JsFunction;
+    return (_randomInt!.apply([max]) as num).toInt();
+  }
+}

lib/src/random/generators.dart

@@ -11,8 +11,12 @@ import 'package:hashlib/src/algorithms/sm3.dart';
 import 'package:hashlib/src/algorithms/xxh64/xxh64.dart';
 import 'package:hashlib/src/core/hash_base.dart';
 
-import 'generator_vm.dart' if (dart.library.js) 'generator_js.dart';
-export 'generator_vm.dart' if (dart.library.js) 'generator_js.dart';
+import 'generator_vm.dart'
+    if (dart.library.html) 'generator_vm.dart'
+    if (dart.library.js) 'generator_js.dart';
+export 'generator_vm.dart'
+    if (dart.library.html) 'generator_vm.dart'
+    if (dart.library.js) 'generator_js.dart';
 
 const int _mask32 = 0xFFFFFFFF;