--- /dev/null
+/*!
+ * is-posix-bracket <https://github.com/jonschlinkert/is-posix-bracket>
+ *
+ * Copyright (c) 2015-2016, Jon Schlinkert.
+ * Licensed under the MIT License.
+ */
+
+module.exports = function isPosixBracket(str) {
+ return typeof str === 'string' && /\[([:.=+])(?:[^\[\]]|)+\1\]/.test(str);
+};