javascript - Assign, and set js object property conditionally

Question

Here's my code:

app.post('/ujfeladat', (req, res) => {
    const {nev, tipus, szid} = req.body;
    const hianyos = () => {
        if(tipus === 'hianyos'){
            return {rang: -1}
        }
        return
    }
    db('fl').insert({
        nev: nev,
        tipus: tipus,
        szid: szid,
        hianyos() //returns an error
    }).returning('*')
    .then(data => res.json(data))
    .catch(err => console.log(err))
})

Answer 1

Updated answer:

Here's how you can do it:

// Will result in { foo: 'foo', bar: 'bar'}
const item = {
  foo: 'foo',
  ... true && { bar: 'bar' },
  ... false && { falsy: 'falsy' },
}

console.log(item)