changes the base instance for ERR_UNKNOWN_FILE_EXTENSION

lib/internal/errors.js

@@ -1001,9 +1001,7 @@ E('ERR_UNHANDLED_ERROR',
     return `${msg} (${err})`;
   }, Error);
 E('ERR_UNKNOWN_ENCODING', 'Unknown encoding: %s', TypeError);
-
-// This should probably be a `TypeError`.
-E('ERR_UNKNOWN_FILE_EXTENSION', 'Unknown file extension: %s', Error);
+E('ERR_UNKNOWN_FILE_EXTENSION', 'Unknown file extension: %s', TypeError);
 E('ERR_UNKNOWN_MODULE_FORMAT', 'Unknown module format: %s', RangeError);
 E('ERR_UNKNOWN_SIGNAL', 'Unknown signal: %s', TypeError);
 E('ERR_UNKNOWN_STDIN_TYPE', 'Unknown stdin file type', Error);

test/es-module/test-esm-loader.js

@@ -0,0 +1,35 @@
+'use strict';
+// Flags: --expose-internals
+
+// This test ensures that resolve and search throw errors appropriately
+
+const common = require('../common');
+const tmpdir = require('../common/tmpdir');
+const { join } = require('path');
+const resolve = require('internal/modules/esm/default_resolve');
+const { writeFileSync, unlinkSync } = require('fs');
+
+const { search } = resolve;
+const unsupported = join(
+  tmpdir.path,
+  'module-with-extension-that-is.unsupported');
+tmpdir.refresh();
+writeFileSync(unsupported, '');
+common.expectsError(
+  () => resolve(unsupported, 'file://' + require.resolve(__filename)),
+  {
+    code: 'ERR_UNKNOWN_FILE_EXTENSION',
+    type: TypeError,
+    message: 'Unknown file extension: ' + unsupported
+  }
+);
+unlinkSync(unsupported);
+
+common.expectsError(
+  () => search('target', undefined),
+  {
+    code: 'ERR_MISSING_MODULE',
+    type: Error,
+    message: 'Cannot find module target'
+  }
+);