getServerSideProps should support props value as Promise (#28607)
Previous to this change, getServerSideProps could only return plain objects
for props, e.g.:
```javascript
export async function getServerSideProps() {
return {
props: {
text: 'some value',
}
}
}
```
With this commit, the props object can also be a Promise, e.g.
```javascript
export async function getServerSideProps() {
return {
props: (async function () {
return {
text: 'promise value',
}
})(),
}
}
```
For now, the framework simply waits for the results of the props Promise to resolve,
but this small change sets the groundwork for later allowing props to be streamed (cc @devknoll).
## Feature
- [x] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR. -- *This is part of @devknoll's ongoing work to support streaming.*
- [ ] Related issues linked using `fixes #number`
- [x] Integration tests added
- [x] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not. *not sure if this applies here*
- [ ] Errors have helpful link attached, see `contributing.md`
next.js
9be387c7 - getServerSideProps should support props value as Promise (#28607)
