some progress

node_modules/mongoose/lib/error/strict.js

@@ -0,0 +1,33 @@
+/*!
+ * Module dependencies.
+ */
+
+'use strict';
+
+const MongooseError = require('./');
+
+
+class StrictModeError extends MongooseError {
+  /**
+   * Strict mode error constructor
+   *
+   * @param {String} path
+   * @param {String} [msg]
+   * @param {Boolean} [immutable]
+   * @inherits MongooseError
+   * @api private
+   */
+  constructor(path, msg, immutable) {
+    msg = msg || 'Field `' + path + '` is not in schema and strict ' +
+      'mode is set to throw.';
+    super(msg);
+    this.isImmutableError = !!immutable;
+    this.path = path;
+  }
+}
+
+Object.defineProperty(StrictModeError.prototype, 'name', {
+  value: 'StrictModeError'
+});
+
+module.exports = StrictModeError;