feat(deno): add Deno support

.github/workflows/nodejs.yml

@@ -32,3 +32,33 @@ jobs:
         run: yarn build
       - name: Run examples
         run: node examples/example.js
+
+  deno:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: ['20', '22', '24', '25']
+    steps:
+      - uses: actions/checkout@v4
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          check-latest: true
+      - name: Cache Node.js modules
+        id: yarn-cache
+        uses: actions/cache@v4
+        with:
+          path: '**/node_modules'
+          key: ${{ runner.os }}-modules-${{ hashFiles('**/yarn.lock') }}-${{ matrix.node-version }}-deno
+      - name: Install dependencies
+        if: steps.yarn-cache.outputs.cache-hit != 'true'
+        run: yarn install
+      - name: Build
+        run: yarn build
+      - name: Setup Deno
+        uses: denoland/setup-deno@v2
+        with:
+          deno-version: v2.x
+      - name: Run Deno integration test
+        run: deno run --allow-read test/integration/deno.ts

README.md

@@ -95,3 +95,19 @@ const defaultOptions = {
   }
 };
 ```
+
+## Deno
+
+`ntp-time-sync` is compatible with Deno. Use the `npm:` specifier to import the package:
+
+```ts
+// Run: deno run --allow-net your-script.ts
+import { NtpTimeSync } from "npm:ntp-time-sync";
+
+const timeSync = NtpTimeSync.getInstance();
+const result = await timeSync.getTime();
+
+console.log("system time", new Date());
+console.log("ntp time", result.now);
+console.log("offset (ms)", result.offset);
+```

examples/deno.ts

@@ -0,0 +1,11 @@
+// Example: using ntp-time-sync with Deno
+// Run: deno run --allow-net examples/deno.ts
+import { NtpTimeSync } from "npm:ntp-time-sync";
+
+const timeSync = NtpTimeSync.getInstance();
+
+console.log("system time", new Date());
+const result = await timeSync.getTime();
+console.log("ntp time", result.now);
+console.log("offset (ms)", result.offset);
+console.log("precision (ms)", result.precision);

package.json

@@ -3,6 +3,7 @@
   "version": "0.5.0",
   "description": "Fetches the current time from NTP servers and returns offset information",
   "main": "dist/index.js",
+  "type": "commonjs",
   "dependencies": {
     "ntp-packet-parser": "^0.5.0"
   },

src/NtpTimeSync.ts

@@ -134,7 +134,9 @@ export class NtpTimeSync {
 
   // @see https://quickref.me/check-if-a-value-is-a-plain-object.html
   private static isPlainObject(v: any): boolean {
-    return !!v && typeof v === "object" && (v.__proto__ === null || v.__proto__ === Object.prototype);
+    if (!v || typeof v !== "object") return false;
+    const proto = Object.getPrototypeOf(v);
+    return proto === null || proto === Object.prototype;
   }
 
   /**

test/integration/deno.ts

@@ -0,0 +1,28 @@
+// Deno integration test — verifies ntp-time-sync works without --unstable-unsafe-proto
+// Run: deno run test/integration/deno.ts
+
+import { createRequire } from "node:module";
+
+const require = createRequire(import.meta.url);
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const { NtpTimeSync } = require("../../dist/index.js");
+
+// Instantiate with nested options to exercise recursiveResolveOptions → isPlainObject
+new NtpTimeSync({
+  sampleCount: 4,
+  ntpDefaults: {
+    minPoll: 4,
+    maxPoll: 10,
+  },
+});
+
+// Verify singleton
+const a = NtpTimeSync.getInstance();
+const b = NtpTimeSync.getInstance();
+if (a !== b) {
+  throw new Error("Singleton check failed: expected same instance");
+}
+
+console.log("✓ NtpTimeSync imported and instantiated");
+console.log("✓ Nested options merged without __proto__ issues");
+console.log("✓ Singleton pattern works");