mongodb node findone how to handle no results using promises

1const assert = require('assert');
2
3schema.static('findMinOne', function(conditions) {
4  return this.find(conditions).then(res => assert.ok(res.length >= 1, 'No documents found'));
5});

1const findUser = async function (params) { 
2    try {  return await User.findOne(params)
3    } catch(err) { console.log(err) }
4}
5
6const userSteve = findUser({firstName: Steve})