add example for gulpjs/glob-parent#39 (comment)

examples/regex-quantifier.js

@@ -0,0 +1,43 @@
+'use strict';
+
+const pico = require('..');
+
+/**
+ * See: https://github.com/gulpjs/glob-parent/issues/39#issuecomment-794075641
+ */
+
+const files = [
+  'data/100-123a_files/0/',
+  'data/100-123a_files/1/',
+  'data/100-123a_files/2/',
+  'data/100-123a_files/3/',
+  'data/100-123b_files/0/',
+  'data/100-123b_files/1/',
+  'data/100-123b_files/2/',
+  'data/100-123b_files/3/',
+  'data/100-123a_files/4/',
+  'data/100-123ax_files/0/',
+  'data/100-123A_files/0/',
+  'data/100-123A_files/1/',
+  'data/100-123A_files/2/',
+  'data/100-123A_files/3/',
+  'data/100-123B_files/0/',
+  'data/100-123B_files/1/',
+  'data/100-123B_files/2/',
+  'data/100-123B_files/3/',
+  'data/100-123A_files/4/',
+  'data/100-123AX_files/0/'
+];
+
+// ? is a wildcard for matching one character
+// by escaping \\{0,3}, and then using `{ unescape: true }, we tell
+// picomatch to treat those characters as a regex quantifier, versus
+// a brace pattern.
+
+const isMatch = pico('data/100-123?\\{0,3}_files/{0..3}/', { unescape: true });
+console.log(files.filter(name => isMatch(name)));
+
+// Alternatively, we can use a regex character class to be more specific
+// In the following example, we'll only match uppercase alpha characters
+const isMatch2 = pico('data/100-123[A-Z]*_files/{0..3}/', { unescape: true });
+console.log(files.filter(name => isMatch2(name)));