docs: update dependency injection examples

[emonddr]

Update dependency injection examples that mention authentication

Related to : #2940

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• npm test passes on your machine
• New tests added or existing tests modified to cover all changes
• Code conforms with the style guide
• API Documentation in code was updated
• Documentation in /docs/site was updated
• Affected artifact templates in packages/cli were updated
• Affected example projects in examples/* were updated

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[jannyHou]

@emonddr I added one more thing to update, otherwise LGTM good update!

The test failures should be fixed after a rebase.

[jannyHou]

@emonddr One more thing to update here:

However, when you want to create a binding that will instantiate a configured class(as a provider) and automatically inject required dependencies, then you need to use .toProvider() method:

server
  .bind(AuthenticationBindings.AUTH_ACTION)
  .toProvider(AuthenticateActionProvider);

const provider = await server.get(AuthenticationBindings.AUTH_ACTION);

[emonddr]

@jannyHou , the existing document used the AuthenticateActionProvider in a .toClass() and in the .toProvider() example.

I've changed the .toClass() example code to use a different class instead; so 1) it is less confusing as to why different binding methods were used on the same class, and 2) so I don't have to change the explanatory paragraph:

[raymondfeng]

In the longer term, I wonder if we should use simpler examples at https://github.com/strongloop/loopback-next/tree/master/examples/context for the DI docs.

[emonddr]

@raymondfeng

In the longer term, I wonder if we should use simpler examples at https://github.com/strongloop/loopback-next/tree/master/examples/context for the DI docs.

Hi Raymond, with the examples I have in place at the moment of my 2nd commit, are you satisfied with the 3 different examples (for the purposes of the authentication documentation changes), and want to create a separate task for modifying these dependency injection examples to be done at a later time? Or are you saying that my PR should use non-authentication examples right now?
Please advise.

[jannyHou]

LGTM please rebase the branch before merging.

[raymondfeng]

Hi Raymond, with the examples I have in place at the moment of my 2nd commit, are you satisfied with the 3 different examples (for the purposes of the authentication documentation changes), and want to create a separate task for modifying these dependency injection examples to be done at a later time? Or are you saying that my PR should use non-authentication examples right now?
Please advise.

I'm fine to use authentication examples for now. It would be ideal to use simpler standalone examples in the future PRs.

[emonddr]

@raymondfeng

I'm fine to use authentication examples for now. It would be ideal to use simpler standalone examples in the future PRs.

Me too. Ok thanks. Can you approve it then? And then I will rebase, etc. Thanks :)