Docs falsely suggest `exec()` for async/await

Do you want to request a feature or report a bug?

Docs.

What is the current docs?

https://mongoosejs.com/docs/promises.html#built-in-promises

This means that you can do things like MyModel.findOne({}).then() and await MyModel.findOne({}).exec() if you’re using async/await.

What is the expected docs?

await Model.findOne() works just fine.

This means that you can do things like MyModel.findOne({}).then() and await MyModel.findOne({}) if you’re using async/await.

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that “latest” is not a version.

Mongoose 5.5.14 Node.js 10.16.2

[jloveridge]

@Moeriki The difference is that the return type of Model.findOne is a Query. They just happen to have added a then to it so it is “thennable” but it is not a true promise. The return from exec is actually a promise if you don’t supply a callback to the exec. While you might not care about this distinction some of us do.

[vkarpov15]

You’re right that queries are not promises: https://mongoosejs.com/docs/queries.html#queries-are-not-promises . The most meaningful difference is that if you await on the same query object twice, you will execute the query twice, whereas await on the same promise twice only executes the query once. We did also run into an issue where node’s async_hooks don’t work properly if you await on a custom thennable, but that’s a node issue that mongoose can’t work around.

TLDR; there are reasons to prefer using exec(), but for most apps it doesn’t matter which one.

@jloveridge I’m curious to hear why you prefer a true promise over a thennable. Is it one of the reasons I listed or something else?