module: warn on invalid package.json type field

src/node_modules.cc

@@ -212,6 +212,16 @@ const BindingData::PackageConfig* BindingData::GetPackageJSON(
       if (value.get_string().get(field_value)) {
         return throw_invalid_package_config();
       }
+
+      if (field_value != "commonjs" && field_value != "module") {
+        ProcessEmitWarning(realm->env(),
+                           "Invalid \"type\" field in package.json: \"%.*s\". "
+                           "Expected \"commonjs\" or \"module\".",
+                           "InvalidPackageType",
+                           static_cast<int>(field_value.size()),
+                           field_value.data());
+      }
+
       // Only update type if it is "commonjs" or "module"
       // The default value is "none" for backward compatibility.
       if (field_value == "commonjs" || field_value == "module") {

test/parallel/test-find-package-json.js

@@ -204,4 +204,6 @@ describe('findPackageJSON', () => { // Throws when no arguments are provided
     assert.ok(stdout.includes(foundPjsonPath), stdout);
     assert.strictEqual(code, 0);
   });
+
+
 });

test/parallel/test-package-json-type-validation.js

@@ -0,0 +1,70 @@
+'use strict';
+
+const common = require('../common');
+const tmpdir = require('../common/tmpdir');
+const assert = require('node:assert');
+const fs = require('node:fs');
+const { describe, it } = require('node:test');
+
+
+describe('package.json type field validation', () => {
+  it('should warn for invalid type field values', async () => {
+    tmpdir.refresh();
+
+    fs.mkdirSync(tmpdir.resolve('invalid-type-pkg'), { recursive: true });
+    fs.writeFileSync(
+      tmpdir.resolve('invalid-type-pkg/package.json'),
+      JSON.stringify({ type: 'CommonJS' })
+    );
+    fs.writeFileSync(
+      tmpdir.resolve('invalid-type-pkg/index.js'),
+      'module.exports = 42;'
+    );
+
+    const { stderr } = await common.spawnPromisified(process.execPath, [
+      tmpdir.resolve('invalid-type-pkg/index.js'),
+    ]);
+
+    assert.ok(stderr.includes('MODULE_INVALID_TYPE'));
+    assert.ok(stderr.includes('CommonJS'));
+  });
+
+  it('should not warn for valid type values', async () => {
+    tmpdir.refresh();
+
+    fs.mkdirSync(tmpdir.resolve('valid-type-pkg'), { recursive: true });
+    fs.writeFileSync(
+      tmpdir.resolve('valid-type-pkg/package.json'),
+      JSON.stringify({ type: 'commonjs' })
+    );
+    fs.writeFileSync(
+      tmpdir.resolve('valid-type-pkg/index.js'),
+      'module.exports = 42;'
+    );
+
+    const { stderr } = await common.spawnPromisified(process.execPath, [
+      tmpdir.resolve('valid-type-pkg/index.js'),
+    ]);
+
+    assert.ok(!stderr.includes('MODULE_INVALID_TYPE'));
+  });
+
+  it('should not warn when type field is missing', async () => {
+    tmpdir.refresh();
+    fs.mkdirSync(tmpdir.resolve('no-type-pkg'), { recursive: true });
+    fs.writeFileSync(
+      tmpdir.resolve('no-type-pkg/package.json'),
+      JSON.stringify({ name: 'test' })
+    );
+    fs.writeFileSync(
+      tmpdir.resolve('no-type-pkg/index.js'),
+      'module.exports = 42;'
+    );
+
+    const { stderr } = await common.spawnPromisified(process.execPath, [
+      tmpdir.resolve('no-type-pkg/index.js'),
+    ]);
+
+    assert.ok(!stderr.includes('MODULE_INVALID_TYPE'));
+  });
+});