What is the difference when accessing a collection then() or .exec()?

Question

Node.js

Works both and everything together

Coll.find().exec()
Coll.find().then()
Coll.find().exec().then()

What is the difference and which is better to use?
In cases with such a sample, everything is clear

Coll.find().then(/**blablabla**/).catch(/**throw**/)

But it can also be done like this

Coll.find().exec().then(/**blablabla**/).catch(/**throw**/)

Answer 1

Just short for I do it myself.

then(thenFn, catchFn) {
  return Promise.resolve(this.run()).then(thenFn, catchFn);
}

Here is the request code from the library

Query.prototype.then = function(resolve, reject) {
  return this.exec().then(resolve, reject);
};