module.exports = function (glob, opts) {
if (typeof glob !== 'string') {
throw new TypeError('Expected a string');
}
var str = String(glob);
// The regexp we are building, as a string.
var reStr = "";
// Whether we are matching so called "extended" globs (like bash) and should
// support single character matching, matching ranges of characters, group
// matching, etc.
var extended = opts ? !!opts.extended : false;
// When globstar is _false_ (default), '/foo/*' is translated a regexp like
// '^\/foo\/.*$' which will match any string beginning with '/foo/'
// When globstar is _true_, '/foo/*' is translated to regexp like
// '^\/foo\/[^/]*$' which will match any string beginning with '/foo/' BUT
// which does not have a '/' to the right of it.
// E.g. with '/foo/*' these will match: '/foo/bar', '/foo/bar.txt' but
// these will not '/foo/bar/baz', '/foo/bar/baz.txt'
// Lastely, when globstar is _true_, '/foo/**' is equivelant to '/foo/*' when
// globstar is _false_
var globstar = opts ? !!opts.globstar : false;
// If we are doing extended matching, this boolean is true when we are inside
// a group (eg {*.html,*.js}), and false otherwise.
var inGroup = false;
// RegExp flags (eg "i" ) to pass in to RegExp constructor.
var flags = opts && typeof( opts.flags ) === "string" ? opts.flags : "";
var c;
for (var i = 0, len = str.length; i < len; i++) {
c = str[i];
switch (c) {
case "/":
case "$":
case "^":
case "+":
case ".":
case "(":
case ")":
case "=":
case "!":
case "|":
reStr += "\\" + c;
break;
case "?":
if (extended) {
reStr += ".";
break;
}
case "[":
case "]":
if (extended) {
reStr += c;
break;
}
case "{":
if (extended) {
inGroup = true;
reStr += "(";
break;
}
case "}":
if (extended) {
inGroup = false;
reStr += ")";
break;
}
case ",":
if (inGroup) {
reStr += "|";
break;
}
reStr += "\\" + c;
break;
case "*":
// Move over all consecutive "*"'s.
// Also store the previous and next characters
var prevChar = str[i - 1];
var starCount = 1;
while(str[i + 1] === "*") {
starCount++;
i++;
}
var nextChar = str[i + 1];
if (!globstar) {
// globstar is disabled, so treat any number of "*" as one
reStr += ".*";
} else {
// globstar is enabled, so determine if this is a globstar segment
var isGlobstar = starCount > 1 // multiple "*"'s
&& (prevChar === "/" || prevChar === undefined) // from the start of the segment
&& (nextChar === "/" || nextChar === undefined) // to the end of the segment
if (isGlobstar) {
// it's a globstar, so match zero or more path segments
reStr += "((?:[^/]*(?:\/|$))*)";
i++; // move over the "/"
} else {
// it's not a globstar, so only match one path segment
reStr += "([^/]*)";
}
}
break;
default:
reStr += c;
}
}
// When regexp 'g' flag is specified don't
// constrain the regular expression with ^ & $
if (!flags || !~flags.indexOf('g')) {
reStr = "^" + reStr + "$";
}
return new RegExp(reStr, flags);
};