node/tools/blog/node_modules/mkdirp/index.js

var path = require('path');
var fs = require('fs');

module.exports = mkdirP.mkdirp = mkdirP.mkdirP = mkdirP;

function mkdirP (p, mode, f, made) {
    if (typeof mode === 'function' || mode === undefined) {
        f = mode;
        mode = 0777 & (~process.umask());
    }
    if (!made) made = null;

    var cb = f || function () {};
    if (typeof mode === 'string') mode = parseInt(mode, 8);
    p = path.resolve(p);

    fs.mkdir(p, mode, function (er) {
        if (!er) {
            made = made || p;
            return cb(null, made);
        }
        switch (er.code) {
            case 'ENOENT':
                mkdirP(path.dirname(p), mode, function (er, made) {
                    if (er) cb(er, made);
                    else mkdirP(p, mode, cb, made);
                });
                break;

            case 'EISDIR':
            case 'EPERM':
                // Operation not permitted or already is a dir.
                // This is the error you get when trying to mkdir('c:/')
                // on windows, or mkdir('/') on unix.  Make sure it's a
                // dir by falling through to the EEXIST case.
            case 'EROFS':
                // a read-only file system.
                // However, the dir could already exist, in which case
                // the EROFS error will be obscuring a EEXIST!
                // Fallthrough to that case.
            case 'EEXIST':
                fs.stat(p, function (er2, stat) {
                    // if the stat fails, then that's super weird.
                    // let the original error be the failure reason.
                    if (er2 || !stat.isDirectory()) cb(er, made)
                    else cb(null, made);
                });
                break;

            default:
                cb(er, made);
                break;
        }
    });
}

mkdirP.sync = function sync (p, mode, made) {
    if (mode === undefined) {
        mode = 0777 & (~process.umask());
    }
    if (!made) made = null;

    if (typeof mode === 'string') mode = parseInt(mode, 8);
    p = path.resolve(p);

    try {
        fs.mkdirSync(p, mode);
        made = made || p;
    }
    catch (err0) {
        switch (err0.code) {
            case 'ENOENT' :
                made = sync(path.dirname(p), mode, made);
                sync(p, mode, made);
                break;

            case 'EEXIST' :
                var stat;
                try {
                    stat = fs.statSync(p);
                }
                catch (err1) {
                    throw err0;
                }
                if (!stat.isDirectory()) throw err0;
                break;
            default :
                throw err0
                break;
        }
    }

    return made;
};