node.js mkdirp

mkdirp.js

var fs = require('fs');

function mkdirp(fn, perms, cb)
// Make a directory and its ancestors if necessary.
{
    // 'perms' is optional, but callback is the last param
    if(arguments.length === 2) {
        cb = arguments[arguments.length-1];
        perms = 0x1fd/*0775*/;
    }

    // To expose a nice interface, we wrap the recursive function itself.
    var _mkdirp = function (e, fn, cb2) {
        // We ignore EEXIST. Lame.
        if(e && e.code !== 'EEXIST') throw e;

        // Create directory recursively, blithely ignoring errors on the way.

        // We start at the leaf (not the root) of the tree, eg. 'a/b/c/d'.

        // So, check if it's a path (eg. 'a/b/c'), or if we're at the root (eg. 'a')
        if(fn.indexOf('/') === -1) {
            // We're at the root of the tree, so we can now start building
            // folders and collapting the tree.
            fs.mkdir(fn, perms, cb2);
        }
        else {
            // It's a path, so recurse: start at a higher level. We want
            // to build a recursion tree with each tail creating the next
            // subfolder. When we've constructed it all, the recursion
            // will collapse, starting with a mkdir of the root folder.
            // Head recursion rocks... honest.
            _mkdirp(null,
                    path.dirname(fn),
                    function (e) {
                        // We ignore EEXIST. Lame.
                        if(e && e.code !== 'EEXIST') throw e;

                        // Okay, we're now collapsing the recursion, so
                        // make the directory and pass to the next mkdir
                        // (the child folder, but the parent function
                        // call!)
                        fs.mkdir(fn, perms, cb2);
                    });
        }
    };

    // Okay, start the recursion.
    _mkdirp(null, fn, function (e) {
        // We ignore EEXIST. Lame.
        if(e && e.code !== 'EEXIST') throw e;
        e = null;
        cb(e);
    });
}