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"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
/* istanbul ignore next */
const Url = (typeof URL !== 'undefined' ? URL : require('url').URL);
// Matches "..", which must be preceeded by "/" or the start of the string, and
// must be followed by a "/". We do not eat the following "/", so that the next
// iteration can match on it.
const parentRegex = /(^|\/)\.\.(?=\/|$)/g;
function isAbsoluteUrl(url) {
try {
return !!new Url(url);
}
catch (e) {
return false;
}
}
/**
* Creates a directory name that is guaranteed to not be in `str`.
*/
function uniqInStr(str) {
let uniq = String(Math.random()).slice(2);
while (str.indexOf(uniq) > -1) {
/* istanbul ignore next */
uniq += uniq;
}
return uniq;
}
/**
* Removes the filename from the path (everything trailing the last "/"). This
* is only safe to call on a path, never call with an absolute or protocol
* relative URL.
*/
function stripPathFilename(path) {
path = normalizePath(path);
const index = path.lastIndexOf('/');
return path.slice(0, index + 1);
}
/**
* Normalizes a protocol-relative URL, but keeps it protocol relative by
* stripping out the protocl before returning it.
*/
function normalizeProtocolRelative(input, absoluteBase) {
const { href, protocol } = new Url(input, absoluteBase);
return href.slice(protocol.length);
}
/**
* Normalizes a simple path (one that has no ".."s, or is absolute so ".."s can
* be normalized absolutely).
*/
function normalizeSimplePath(input) {
const { href } = new Url(input, 'https://foo.com/');
return href.slice('https://foo.com/'.length);
}
/**
* Normalizes a path, ensuring that excess ".."s are preserved for relative
* paths in the output.
*
* If the input is absolute, this will return an absolutey normalized path, but
* it will not have a leading "/".
*
* If the input has a leading "..", the output will have a leading "..".
*
* If the input has a leading ".", the output will not have a leading "."
* unless there are too many ".."s, in which case there will be a leading "..".
*/
function normalizePath(input) {
// If there are no ".."s, we can treat this as if it were an absolute path.
// The return won't be an absolute path, so it's easy.
if (!parentRegex.test(input))
return normalizeSimplePath(input);
// We already found one "..". Let's see how many there are.
let total = 1;
while (parentRegex.test(input))
total++;
// If there are ".."s, we need to prefix the the path with the same number of
// unique directories. This is to ensure that we "remember" how many parent
// directories we are accessing. Eg, "../../.." must keep 3, and "foo/../.."
// must keep 1.
const uniqDirectory = `z${uniqInStr(input)}/`;
// uniqDirectory is just a "z", followed by numbers, followed by a "/". So
// generating a runtime regex from it is safe. We'll use this search regex to
// strip out our uniq directory names and insert any needed ".."s.
const search = new RegExp(`^(?:${uniqDirectory})*`);
// Now we can resolve the total path. If there are excess ".."s, they will
// eliminate one or more of the unique directories we prefix with.
const relative = normalizeSimplePath(uniqDirectory.repeat(total) + input);
// We can now count the number of unique directories that were eliminated. If
// there were 3, and 1 was eliminated, we know we only need to add 1 "..". If
// 2 were eliminated, we need to insert 2 ".."s. If all 3 were eliminated,
// then we need 3, etc. This replace is guranteed to match (it may match 0 or
// more times), and we can count the total match to see how many were eliminated.
return relative.replace(search, (all) => {
const leftover = all.length / uniqDirectory.length;
return '../'.repeat(total - leftover);
});
}
/**
* Attempts to resolve `input` URL relative to `base`.
*/
function resolve(input, base) {
if (!base)
base = '';
// Absolute URLs are very easy to resolve right.
if (isAbsoluteUrl(input))
return new Url(input).href;
if (base) {
// Absolute URLs are easy...
if (isAbsoluteUrl(base))
return new Url(input, base).href;
// If base is protocol relative, we'll resolve with it but keep the result
// protocol relative.
if (base.startsWith('//'))
return normalizeProtocolRelative(input, `https:${base}`);
}
// Normalize input, but keep it protocol relative. We know base doesn't supply
// a protocol, because that would have been handled above.
if (input.startsWith('//'))
return normalizeProtocolRelative(input, 'https://foo.com/');
// We now know that base (if there is one) and input are paths. We've handled
// both absolute and protocol-relative variations above.
// Absolute paths don't need any special handling, because they cannot have
// extra "." or ".."s. That'll all be stripped away. Input takes priority here,
// because if input is an absolute path, base path won't affect it in any way.
if (input.startsWith('/'))
return '/' + normalizeSimplePath(input);
// Since input and base are paths, we need to join them to do any further
// processing. Paths are joined at the directory level, so we need to remove
// the base's filename before joining. We also know that input does not have a
// leading slash, and that the stripped base will have a trailing slash if
// there are any directories (or it'll be empty).
const joined = stripPathFilename(base) + input;
// If base is an absolute path, then input will be relative to it.
if (base.startsWith('/'))
return '/' + normalizeSimplePath(joined);
// We now know both base (if there is one) and input are relative paths.
const relative = normalizePath(joined);
// If base started with a leading ".", or there is no base and input started
// with a ".", then we need to ensure that the relative path starts with a
// ".". We don't know if relative starts with a "..", though, so check before
// prepending.
if ((base || input).startsWith('.') && !relative.startsWith('.')) {
return './' + relative;
}
return relative;
}
exports.default = resolve;
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