Documentation of loopback 4 Model is incorrect

[opepermans]

Description/Steps to reproduce

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Expected result

Additional information

[dhmlau]

@opepermans, could you please elaborate which part of the documentation is incorrect? Thanks!

[opepermans]

In https://loopback.io/doc/en/lb4/Model.html#model-decorator there is a hyperlink to https://loopback.io/doc/en/lb3/Model-definition-JSON-file.html which describes properties that are not valid in lb4. E.g. "options" (https://loopback.io/doc/en/lb3/Model-definition-JSON-file.html#options) was used to set the database schema while it now should be:

@model({
  settings: {
     postgresql: {
        schema: 't1'
     }
  }
})

So I think the hyperlink to https://loopback.io/doc/en/lb3/Model-definition-JSON-file.html should be removed and instead there should be an in depth explanation of the lb4 model-decorator properties.

[dhmlau]

Thanks @opepermans. I agree some part of https://loopback.io/doc/en/lb3/Model-definition-JSON-file.html not applicable to LB4. In fact, the ModelDefinitionSyntax (https://github.com/strongloop/loopback-next/blob/master/packages/repository/src/model.ts#L58) is the source of truth.

[emonddr]

We need to groom this to determine if we want an lb4 version of the https://loopback.io/doc/en/lb3/Model-definition-JSON-file.html .

[dhmlau]

Instead of finding which content in https://loopback.io/doc/en/lb3/Model-definition-JSON-file.html we can reuse in LB4, I think we can think the other way round to beef up the docs for Model Decorator and Property Decorator, and see if there's anything applicable in the LB3 docs we can reuse so that we don't need to write it from scratch.

• Model decorator
  • what's expected in properties? Is it https://loopback.io/doc/en/lb3/Model-definition-JSON-file.html#properties?
  • what's expected in settings? Is it everything in https://loopback.io/doc/en/lb3/Model-definition-JSON-file.html#options?
• Property Decorator
  • what are the valid values? would it be what's in the table for general properties?

[b-admike]

Based on the discussion in this thread, I've compiled the following criteria for this issue.

Acceptance Criteria

• Figure out what can be passed into the model decorator (top-level) and how that affects the LoopBack 4 application. Because we are using legacy juggler bridge, we need to find out if the mapping of top-level keys works OOTB. For example, does passing in @model({options:{...}}) work similar to how it does in LB3? The main keys to examine are properties, settings, options, relations because they're used often, but it'd be good to check all with a test app. Explain this in docs for Model Decorator. Use https://loopback.io/doc/en/lb3/Model-definition-JSON-file.html as the base to compare to and document differences.
• Figure out valid values for Property Decorator and explain them in more depth. Explore compliance with https://loopback.io/doc/en/lb3/Model-definition-JSON-file.html#general-property-properties and document discrepancies.
• For keys that do not work the same in LB4 as they do in LB3, create follow-up stories.