需要有关JavaScript递归和异步方法的建议

Question

I have a recursive method that has, contained within, a async method:

var loadWebsRecursively = function (url) {

    loadWebsDeferred(url).then(function (webs) {

        var wE = webs.getEnumerator();
        webCount += webs.get_count();
        while (wE.moveNext()) {
            var site = wE.get_current();
            var title = site.get_title().toLowerCase();
            var fqdn = siteRootUrl + site.get_serverRelativeUrl() + '/';
            .... // additional work
        }

         webProcessed++;
         loadWebsRecursively(fqdn);
    }
};

I need some suggestions on how I can determine that all recursive calls have finished. Each Web could have "N" number of sub-webs.

Thanks in advance!

Answer 1

It seems that you are looking to resolve a promise sequence. If you're using javascript's native ES6 promise implementation, then something like the following might be what you're looking for:

// Loop through our chapter urls
story.chapterUrls.reduce(function(sequence, chapterUrl) {
  // Add these actions to the end of the sequence
  return sequence.then(function() {
    return getJSON(chapterUrl);
  }).then(function(chapter) {
    addHtmlToPage(chapter.html);
  });
}, Promise.resolve());

See here for more details:
http://www.html5rocks.com/en/tutorials/es6/promises/#toc-parallelism-sequencing