Move internal modules to “internal” folder.

.internal/baseIsArrayBuffer.js

@@ -0,0 +1,17 @@
+import baseGetTag from './.internal/baseGetTag.js';
+import isObjectLike from './isObjectLike.js';
+
+const arrayBufferTag = '[object ArrayBuffer]';
+
+/**
+ * The base implementation of `isArrayBuffer` without Node.js optimizations.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is an array buffer, else `false`.
+ */
+function baseIsArrayBuffer(value) {
+  return isObjectLike(value) && baseGetTag(value) == arrayBufferTag;
+}
+
+export default baseIsArrayBuffer;