Estructura inicial del proyecto

backend/node_modules/mongoose/lib/helpers/query/hasDollarKeys.js

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+'use strict';
+
+/*!
+ * ignore
+ */
+
+module.exports = function hasDollarKeys(obj) {
+
+  if (typeof obj !== 'object' || obj === null) {
+    return false;
+  }
+
+  const keys = Object.keys(obj);
+  const len = keys.length;
+
+  for (let i = 0; i < len; ++i) {
+    if (keys[i][0] === '$') {
+      return true;
+    }
+  }
+
+  return false;
+};