How to use promise to avoid callback hell? [duplicate]

Answer 1

Try whit this:

function getPost(id) {
  return Post
    .findOne({id: id})
    .then( post => {
      return post;
    });
}

using Q module

function getCommentsAndLinks(post) {
  return Q.all([
    Comment.find({id: post.id}),
    Links.find({id: post.id})
  ])
  .done( results => {
    let comments = results[0];
    let links = results[1];
    return [post, comments, links];
  })
  .catch( err => {
  // handle err
  })

on controller

getPost(postId)
.then(getCommentsAndLinks)
.then( results => {
  let post = results[0];
  let comments = results[1];
  let links = results[2];
  // more code here
})
.catch( err => {
// handle err
}) 

but i suggest you not save string of IDS, save the instance of object, so you can use populate to get all data of comments and links, something like this:

Post
.findOne({id: id})
.populate('comments')
.populate('links')
.then( post => {
    // here have the post with data of comments and links
});