weex-nuke/lib/node_modules/nuke-util/src/realpath.js

基于 Rax 、Weex 的高性能组件体系 ~~

var DIRNAME_RE = /[^?#]*\//;

var DOT_RE = /\/\.\//g;
var DOUBLE_DOT_RE = /\/[^/]+\/\.\.\//;
var MULTI_SLASH_RE = /([^:/])\/+\//g;

// Extract the directory portion of a path
// dirname("a/b/c.js?t=123#xx/zz") ==> "a/b/"
// ref: http://jsperf.com/regex-vs-split/2
function dirname(path) {
  return path.match(DIRNAME_RE)[0];
}

// Canonicalize a path
// realpath("http://test.com/a//./b/../c") ==> "http://test.com/a/c"
function realpath(path) {
  // /a/b/./c/./d ==> /a/b/c/d
  path = path.replace(DOT_RE, '/');

  /*
    @author wh1100717
    a//b/c ==> a/b/c
    a///b/////c ==> a/b/c
    DOUBLE_DOT_RE matches a/b/c//../d path correctly only if replace // with / first
  */
  path = path.replace(MULTI_SLASH_RE, '$1/');

  // a/b/c/../../d  ==>  a/b/../d  ==>  a/d
  while (path.match(DOUBLE_DOT_RE)) {
    path = path.replace(DOUBLE_DOT_RE, '/');
  }

  return path;
}
module.exports = realpath;