* chore: run unit tests on node 10.15
We saw in https://github.com/puppeteer/puppeteer/issues/6548 that the
`fs.promises` module was experimental in Node <10.17 and as such we
introduced issues for users on 10.15.
Until we can drop Node v10 (it's EOL is 30-04-20201
https://github.com/nodejs/Release#release-schedule) we should run our
tests on an old Node 10 to avoid regressing in this area.
* chore: helper for importing fs safely
In `src/common` we now use `fs.promises.X` which we can dynamically
`import`. In a browser environment this code will never run because it's
gated on `isNode` (in a future PR we will add tree-shaking to the bundle
step such that this code is eliminated). By using `import`, we ensure
TypeScript still can track types and give good type information.
In `src/node` we continue to use `util.promisify` but that's not a
concern as that code explicitly is never run in the browser.
This commit changes the internal representation of query handlers to contain Puppeteer-level code instead of page functions.
The interface `CustomQueryHandler` is introduced for user-defined query handlers. When a `CustomQueryHandler` is registered using `registerCustomQueryHandler` a corresponding Puppeteer-level handler is created through `makeQueryHandler` by wrapping the page functions as appropriate.
The internal query handlers (defined by the interface `QueryHandler`) contain two new functions: `waitFor` and `queryAllArray`.
- `waitFor` allows page-based handlers to make use of the `WaitTask`-backed implementation in `DOMWorld`, whereas purely Puppeteer-based handlers can define an alternative approach instead.
- `queryAllArray` is similar to `queryAll` but with a slightly different interface; it returns a `JSHandle` to an array with the results as opposed to an array of `ElementHandle`. It is used by `$$eval`.
After this change, we can introduce built-in query handlers that are not executed in the page context (#6307).
The logic for waitForXPath and waitForSelector is currently very tightly coupled. This commit tries to untangle that relationship. This is the first step towards introducing built-in query handlers that are not executed in the page context (#6307).
* chore: enforce file extensions on imports
To make our output agnostic it should include file extensions in the
output, as per the ESM spec. It's a bit odd for Node packages but makes
it easier to publish a browser build.
I noticed that DOMWorld was spitting a lot of warnings out when we
generated the docs. It was mostly easy tidy-ups and removing old JSDoc
comments and now the warnings are gone :)
* chore(docs): reduce warnings when generating docs
This is a bunch of small miscellaneous fixes that reduce the amount of
warnings logged when generating our new docs. The long term goal is to
get this list down to 0 warnings, but I'll do it in multiple PRs.
* satisfy doclint
This pulls in the types (based on the DefinitelyTyped repo) for
`page.$eval` (and the `$eval` method on other classes). The `$eval`
method is quite hard to type due to the way we wrap and unwrap
ElementHandles that are passed to / returned from the `pageFunction`
that users provide.
Longer term we can improve the types by providing type overloads as
DefinitelyTyped does but I've deferred that for now (see the `TODO` in
the code for more details).
This change started as a small change to pull types from DefinitelyTyped over to
Puppeteer for the `evaluateHandle` function but instead ended up also fixing
what looks to be a long standing issue with our existing documentation.
`evaluateHandle` can in fact return an `ElementHandle` rather than a `JSHandle`.
Note that `ElementHandle` extends `JSHandle` so whilst the docs are technically
correct (all ElementHandles are JSHandles) it's confusing because JSHandles
don't have methods like `click` on them, but ElementHandles do.
if you return something that is an HTML element:
```
const button = page.evaluateHandle(() => document.querySelector('button'));
// this is an ElementHandle, not a JSHandle
```
Therefore I've updated the original docs and added a large explanation to the
TSDoc for `page.evaluateHandle`.
In TypeScript land we'll assume the function will return a `JSHandle` but you
can tell TS otherwise via the generic argument, which can only be `JSHandle`
(the default) or `ElementHandle`:
```
const button = page.evaluateHandle<ElementHandle>(() => document.querySelector('button'));
```
* feat(types): improve typing of `.evaluate()`
This is the start of the work to take the types from the
`@types/puppeteer` repository and port them into our repo so we can ship
our built-in types out the box.
This change types the `evaluate` function properly. It takes a generic
type which is the type of the function you're passing, and the arguments
and the return that you get back from the `evaluate` call are typed
correctly.
DOMWorld only needs to use Node's `fs` module if you're adding a
filepath as a script/style tag. We can detect this case and run the
`require` inline such that in a browser this code won't execute.
These files will be used by both the web and node versions of Puppeteer.
Another name for this might be "core" but I don't want to cause
confusion with the puppeteer-core package that we publish at the moment.
