Move internal modules to “internal” folder.

.internal/getSymbolsIn.js

@@ -0,0 +1,25 @@
+import arrayPush from './.internal/arrayPush.js';
+import getPrototype from './.internal/getPrototype.js';
+import getSymbols from './.internal/getSymbols.js';
+import stubArray from './stubArray.js';
+
+/* Built-in method references for those with the same name as other `lodash` methods. */
+const nativeGetSymbols = Object.getOwnPropertySymbols;
+
+/**
+ * Creates an array of the own and inherited enumerable symbols of `object`.
+ *
+ * @private
+ * @param {Object} object The object to query.
+ * @returns {Array} Returns the array of symbols.
+ */
+const getSymbolsIn = !nativeGetSymbols ? stubArray : object => {
+  const result = [];
+  while (object) {
+    arrayPush(result, getSymbols(object));
+    object = getPrototype(object);
+  }
+  return result;
+};
+
+export default getSymbolsIn;