CODEWITHSUNDEEP
promisebluebirdbookshelf.jsknex.js
Mike Jonas
Mike Jonas

Reputation: 333

Bookshelf / knex sorting with descending order then limiting results

I'm looking to reverse and limit results. Reversing works fine, limiting works fine, but chained together, the results aren't how I expect. If limit is set to 10 I get 0 results. If it's set to 200 I get 6 results. Any idea what's causing this?

Users .query(q => { q.orderBy('id', 'DESC').limit(10) }) .fetch({withRelated: ['groups']}) .then(function(users) { util.filterUsers(users.map(function(user) { var groups = user.related('groups'); return { id: user.id, handle: user.get('handle'), githubid: user.get('githubid'), name: user.get('name'), public: user.get('public'), url: user.get('url_hash'), image: user.get('image'), email: user.get('email'), groups: groups.reduce(function(prev, group) { prev[group.id] = group.get('group_name'); return prev; }, {}), }; }), req.user.id) .then((results) => { res.status(200).send(results); });

Upvotes: 1

Views: 1026

Answers (2)

Muhammad Raihan Muhaimin
Muhammad Raihan Muhaimin

Reputation: 5729

You need to add a return statement before your function util.filterUsers. Try this

Users
      .query(q => {
          q.orderBy('id', 'DESC').limit(10);
      })
      .fetch({withRelated: ['groups']})
      .then(function(users) {
          return util.filterUsers(users.map(function(user) {
              var groups = user.related('groups');
              return {
                  id: user.id,
                  handle: user.get('handle'),
                  githubid: user.get('githubid'),
                  name: user.get('name'),
                  public: user.get('public'),
                  url: user.get('url_hash'),
                  image: user.get('image'),
                  email: user.get('email'),
                  groups: groups.reduce(function(prev, group) {
                      prev[group.id] = group.get('group_name');
                      return prev;
                  }, {})
              };
          }), req.user.id);
      })
      .then((results) => {
          res.status(200).send(results);
      });

Upvotes: 1

flaviodesousa
flaviodesousa

Reputation: 7815

Each then() is expected to return a promise itself. If a common value is returned Bluebird (Bookshelf's choice for Promises) turns it into a promise itself.

In your case the then(function(users) {...}) is not returning anything, so it should be replaced by tap(function(users) {...}). See tap on Bluebird documentation.

But IF util.filterUsers(...); transforms the list somehow and it is a promise itself, you MUST return it, so placing its invocation under a return statement: return util.filterUsers(...);. In this case it is possible that it returns fewer users than the amount requested (that's what filters usually do...).

Upvotes: 2

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