So don’t use distinct(). You find() and omit the duplicate results. Something like:
wixData.query("DB")
.ascending('index')
.limit(1000)
.find()
.then( (res) => {
let results = res.items.map(e => e.itemName);
results = results.filter((e, index) => results.indexOf(e) === index);
console.log(results);
})
Apparently you can’t sort distinct() based on other fields (but it’s not documented)