## Changes
- Migrate class based `_document`s to functional documents
- Removed `_document.js` where default
- Removed `MyDocument.getInitialProps` where default
## Motivation
This removes some boilerplate and prepares examples for server components.
## Documentation / Examples
- [x] Make sure the linting passes by running `pnpm lint`
- [x] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
The [with-facebook-pixel](https://github.com/vercel/next.js/tree/canary/examples/with-facebook-pixel) example attempts to run the <Script /> loading the Facebook Pixel on every request. This results in a warning stating `[Meta Pixel] - Duplicate Pixel ID: xxx`. According to the Next.js docs, by using an [id on the inline script](https://nextjs.org/docs/basic-features/script#inline-scripts) Next is able to track and optimize the script. Since this is absent on the present example, the inline script is continuously loaded on every request.
I've added an id to this inline script, and the warning from facebook is no longer present.
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [x] Make sure the linting passes by running `yarn lint`
Co-authored-by: Balázs Orbán <18369201+balazsorban44@users.noreply.github.com>
## Problems with the other implementation
- pixel not working first time load page (this generate fake information to facebook analytics data)
- package react-facebook-pixel error when try use events in code blocks or other pages with the current implementation
- sometimes pixel mark twice pageview (this generate warning in facebook panel)
- standar or custom events not working
## Solutions
- Initialize pixel when entering each page (_document)
- Now, we can use custom and standar events (utils/fpixel.js)
- correct way to implement pixel according to facebook and guide facebook to implement in SPA
- this solution is complemented with example "with-google-analytics"
In my opinion, the other development has problems, but I preferred created a new example because the way to implement the base code is different. It seems that the other example is based on set the events from the Facebook control panel then this method limits an advanced implementation.
