Using promises with mongoose functions

Question

I'm new to promises. And I'm trying to use them with mongoose query functions like find() and findById(). Everything seems to work but I'm not sure if this is the correct way of chaining then. The objective of using promises is to eliminate callback hell but the way I'm chaining then looks very similar to callbacks. Is there a better way to write this route?

router.get('/homehr/employees/new', middleware.isLoggedInAsHR, (req, res) => {
Department.find({})
    .exec()
    .then((allDepartments) => {
        Employee.findById(req.user.employee.id)
        .exec()
        .then((foundEmployee) => {
            res.render('hr/employees/new', {
                departments: allDepartments,
                employee: foundEmployee,
                blogs: allBlogs
            });
        });
    })
    .catch((err) => {
        console.log(err);
        req.flash('error', err.message);
        return res.redirect('back');
    });
});

You should definitely switch to async/await. This is the ultimate callback hell solution. — Wiktor Zychla
– Wiktor Zychla, Commented Apr 19, 2020 at 12:06
You seems to miss Your Blog fetching from database , but using allBlogs as variable. — Gaurav
– Gaurav, Commented Apr 19, 2020 at 12:26

Abhishek Singh · Accepted Answer · 2020-04-19 12:25:22Z

1

Your Routes doesn't seems to have dependency of fetching models in sequence. So You can write this in more better way as follow:

router.get('/homehr/employees/new', middleware.isLoggedInAsHR, async (req, res) => {
   try{
      const allDepartments = await Department.find({});
      const foundEmployee = await Employee.findById(req.user.employee.id);
      res.render('hr/employees/new', {
          departments: allDepartments,
          employee: foundEmployee,
          blogs: allBlogs
      });
   }catch(err){
       console.log(err);
       req.flash('error', err.message);
       return res.redirect('back');
   }
)};

edited Apr 19, 2020 at 12:25

Abhishek Singh

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answered Apr 19, 2020 at 12:20

Gaurav

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1 Comment

Kassaï-迈克-Kaym Over a year ago

This worked thanks a lot for your answer. I didn't learn async/await yet but this seems to get rid of code indentation problem.

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