78 lines
1.7 KiB
JavaScript
78 lines
1.7 KiB
JavaScript
'use strict';
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function isAbsolute(pathname) {
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return pathname.charAt(0) === '/';
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}
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// About 1.5x faster than the two-arg version of Array#splice()
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function spliceOne(list, index) {
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for (var i = index, k = i + 1, n = list.length; k < n; i += 1, k += 1) {
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list[i] = list[k];
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}
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list.pop();
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}
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// This implementation is based heavily on node's url.parse
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function resolvePathname(to, from) {
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if (from === undefined) from = '';
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var toParts = (to && to.split('/')) || [];
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var fromParts = (from && from.split('/')) || [];
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var isToAbs = to && isAbsolute(to);
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var isFromAbs = from && isAbsolute(from);
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var mustEndAbs = isToAbs || isFromAbs;
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if (to && isAbsolute(to)) {
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// to is absolute
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fromParts = toParts;
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} else if (toParts.length) {
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// to is relative, drop the filename
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fromParts.pop();
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fromParts = fromParts.concat(toParts);
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}
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if (!fromParts.length) return '/';
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var hasTrailingSlash;
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if (fromParts.length) {
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var last = fromParts[fromParts.length - 1];
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hasTrailingSlash = last === '.' || last === '..' || last === '';
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} else {
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hasTrailingSlash = false;
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}
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var up = 0;
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for (var i = fromParts.length; i >= 0; i--) {
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var part = fromParts[i];
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if (part === '.') {
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spliceOne(fromParts, i);
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} else if (part === '..') {
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spliceOne(fromParts, i);
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up++;
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} else if (up) {
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spliceOne(fromParts, i);
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up--;
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}
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}
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if (!mustEndAbs) for (; up--; up) fromParts.unshift('..');
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if (
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mustEndAbs &&
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fromParts[0] !== '' &&
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(!fromParts[0] || !isAbsolute(fromParts[0]))
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)
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fromParts.unshift('');
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var result = fromParts.join('/');
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if (hasTrailingSlash && result.substr(-1) !== '/') result += '/';
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return result;
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}
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module.exports = resolvePathname;
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