Convert a glob string to a regular expression.

Tries to match bash glob expansion as closely as possible.

Basic glob syntax:

• * - Matches everything without leaving the path segment.
• {foo,bar} - Matches foo or bar.
• [abcd] - Matches a, b, c or d.
• [a-d] - Matches a, b, c or d.
• [!abcd] - Matches any single character besides a, b, c or d.
• [[:<class>:]] - Matches any character belonging to <class>.
  • [[:alnum:]] - Matches any digit or letter.
  • [[:digit:]abc] - Matches any digit, a, b or c.
  • See https://facelessuser.github.io/wcmatch/glob/#posix-character-classes for a complete list of supported character classes.
• \ - Escapes the next character for an os other than "windows".
• ` - Escapes the next character for os set to "windows".
• / - Path separator.
• \ - Additional path separator only for os set to "windows".

Extended syntax:

• Requires { extended: true }.
• ?(foo|bar) - Matches 0 or 1 instance of {foo,bar}.
• @(foo|bar) - Matches 1 instance of {foo,bar}. They behave the same.
• *(foo|bar) - Matches n instances of {foo,bar}.
• +(foo|bar) - Matches n > 0 instances of {foo,bar}.
• !(foo|bar) - Matches anything other than {foo,bar}.
• See https://www.linuxjournal.com/content/bash-extended-globbing.

Globstar syntax:

• Requires { globstar: true }.
• ** - Matches any number of any path segments.
  • Must comprise its entire path segment in the provided glob.
• See https://www.linuxjournal.com/content/globstar-new-bash-globbing-option.

Note the following properties:

• The generated RegExp is anchored at both start and end.
• Repeating and trailing separators are tolerated. Trailing separators in the provided glob have no meaning and are discarded.
• Absolute globs will only match absolute paths, etc.
• Empty globs will match nothing.
• Any special glob syntax must be contained to one path segment. For example, ?(foo|bar/baz) is invalid. The separator will take precendence and the first segment ends with an unclosed group.
• If a path segment ends with unclosed groups or a dangling escape prefix, a parse error has occured. Every character for that segment is taken literally in this event.

Limitations:

• A negative group like !(foo|bar) will wrongly be converted to a negative look-ahead followed by a wildcard. This means that !(foo).js will wrongly fail to match foobar.js, even though foobar is not foo. Effectively, !(foo|bar) is treated like !(@(foo|bar)*). This will work correctly if the group occurs not nested at the end of the segment.