Move internal modules to “internal” folder.

.internal/asciiToArray.js

@@ -0,0 +1,12 @@
+/**
+ * Converts an ASCII `string` to an array.
+ *
+ * @private
+ * @param {string} string The string to convert.
+ * @returns {Array} Returns the converted array.
+ */
+function asciiToArray(string) {
+  return string.split('');
+}
+
+export default asciiToArray;