lib: add navigator.hardwareConcurrency

Co-authored-by: Mestery <[email protected]>
Co-authored-by: Voltrex <[email protected]>

.eslintrc.js

@@ -327,6 +327,7 @@ module.exports = {
     DecompressionStream: 'readable',
     fetch: 'readable',
     FormData: 'readable',
+    navigator: 'readable',
     ReadableStream: 'readable',
     ReadableStreamDefaultReader: 'readable',
     ReadableStreamBYOBReader: 'readable',

doc/api/globals.md

@@ -583,6 +583,32 @@ The `MessagePort` class. See [`MessagePort`][] for more details.
 
 This variable may appear to be global but is not. See [`module`][].
 
+## `navigator`
+
+<!-- YAML
+  added: REPLACEME
+-->
+
+> Stability: 1 - Experimental
+>
+> An implementation of the [Navigator API][]. Similar to [`window.navigator`][]
+> in browsers.
+
+### `navigator.hardwareConcurrency`
+
+<!-- YAML
+  added: REPLACEME
+-->
+
+* {number}
+
+The navigator.hardwareConcurrency read-only property returns the number of
+logical processors available to run threads on the user's computer.
+
+```js
+console.log(`This process is running on ${navigator.hardwareConcurrency}`);
+```
+
 ## `PerformanceEntry`
 
 <!-- YAML
@@ -998,6 +1024,7 @@ A browser-compatible implementation of [`WritableStreamDefaultWriter`][].
 
 [CommonJS module]: modules.md
 [ECMAScript module]: esm.md
+[Navigator API]: https://html.spec.whatwg.org/multipage/system-state.html#the-navigator-object
 [Web Crypto API]: webcrypto.md
 [`--no-experimental-fetch`]: cli.md#--no-experimental-fetch
 [`--no-experimental-global-customevent`]: cli.md#--no-experimental-global-customevent
@@ -1057,6 +1084,7 @@ A browser-compatible implementation of [`WritableStreamDefaultWriter`][].
 [`setInterval`]: timers.md#setintervalcallback-delay-args
 [`setTimeout`]: timers.md#settimeoutcallback-delay-args
 [`structuredClone`]: https://developer.mozilla.org/en-US/docs/Web/API/structuredClone
+[`window.navigator`]: https://developer.mozilla.org/en-US/docs/Web/API/Window/navigator
 [buffer section]: buffer.md
 [built-in objects]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects
 [module system documentation]: modules.md

lib/.eslintrc.yaml

@@ -75,6 +75,8 @@ rules:
       message: Use `const { MessageEvent } = require('internal/worker/io');` instead of the global.
     - name: MessagePort
       message: Use `const { MessagePort } = require('internal/worker/io');` instead of the global.
+    - name: Navigator
+      message: Use `const navigator = require('internal/navigator');` instead of the global.
     - name: PerformanceEntry
       message: Use `const { PerformanceEntry } = require('perf_hooks');` instead of the global.
     - name: PerformanceMark

lib/internal/bootstrap/node.js

@@ -224,6 +224,15 @@ defineLazyProperties(
   ['structuredClone'],
 );
 
+// https://html.spec.whatwg.org/multipage/system-state.html#the-navigator-object
+ObjectDefineProperty(globalThis, 'navigator', {
+  __proto__: null,
+  enumerable: true,
+  configurable: true,
+  writable: false,
+  value: require('internal/navigator'),
+});
+
 // Set the per-Environment callback that will be called
 // when the TrackingTraceStateObserver updates trace state.
 // Note that when NODE_USE_V8_PLATFORM is true, the observer is

lib/internal/navigator.js

@@ -0,0 +1,28 @@
+'use strict';
+
+const {
+  ObjectDefineProperties,
+} = primordials;
+
+const {
+  kEnumerableProperty,
+} = require('internal/util');
+
+const {
+  getAvailableParallelism,
+} = internalBinding('os');
+
+class Navigator {
+  /**
+   * @return {number}
+   */
+  get hardwareConcurrency() {
+    return getAvailableParallelism();
+  }
+}
+
+ObjectDefineProperties(Navigator.prototype, {
+  hardwareConcurrency: kEnumerableProperty,
+});
+
+module.exports = new Navigator();

test/common/index.js

@@ -309,6 +309,10 @@ if (global.gc) {
   knownGlobals.push(global.gc);
 }
 
+if (global.navigator) {
+  knownGlobals.push(global.navigator);
+}
+
 if (global.Performance) {
   knownGlobals.push(global.Performance);
 }

test/parallel/test-bootstrap-modules.js

@@ -46,6 +46,8 @@ const expectedModules = new Set([
   'NativeModule async_hooks',
   'NativeModule internal/process/task_queues',
   'NativeModule timers',
+  'Internal Binding os',
+  'NativeModule internal/navigator',
   'Internal Binding trace_events',
   'NativeModule internal/constants',
   'NativeModule path',

test/parallel/test-global.js

@@ -49,6 +49,7 @@ builtinModules.forEach((moduleName) => {
     'clearImmediate',
     'clearInterval',
     'clearTimeout',
+    'navigator',
     'atob',
     'btoa',
     'performance',

test/parallel/test-navigator.js

@@ -0,0 +1,15 @@
+'use strict';
+
+require('../common');
+const assert = require('assert');
+
+const is = {
+  number: (value, key) => {
+    assert(!Number.isNaN(value), `${key} should not be NaN`);
+    assert.strictEqual(typeof value, 'number');
+  },
+};
+
+is.number(+navigator.hardwareConcurrency, 'hardwareConcurrency');
+is.number(navigator.hardwareConcurrency, 'hardwareConcurrency');
+assert.ok(navigator.hardwareConcurrency > 0);