nodejs: remove empty directories recursively

cleanEmptyFoldersRecursively.js

  function cleanEmptyFoldersRecursively(folder) {
    var fs = require('fs');
    var path = require('path');

    var isDir = fs.statSync(folder).isDirectory();
    if (!isDir) {
      return;
    }
    var files = fs.readdirSync(folder);
    if (files.length > 0) {
      files.forEach(function(file) {
        var fullPath = path.join(folder, file);
        cleanEmptyFoldersRecursively(fullPath);
      });

      // re-evaluate files; after deleting subfolder
      // we may have parent folder empty now
      files = fs.readdirSync(folder);
    }

    if (files.length == 0) {
      console.log("removing: ", folder);
      fs.rmdirSync(folder);
      return;
    }
  }

Very clever with the second if statement and reloading the files before. I was banging my head against reverse recursion issues, and that solved it. Nice work!

Thanks! I ported it to an ES module (and shortened it a bit): https://gist.github.com/arnoson/3237697e8c61dfaf0356f814b1500d7b

@arnoson Very nice. In case anyone needs a version which excludes certain directories from the traversal (such as the ubiquitous node_modules/ directory), here is a slight revision I made -- this should work for Typescript/Node:
https://gist.github.com/rnag/a5e8dcea68979a5df4a946e41f75ea97

Measuring performance, I noted a huge improvement in my case. ~100 milliseconds down to ~1 millisecond. The reason is that otherwise it was traversing down a node_modules subfolder which had a ton of folders underneath it that it need to separately check.