Support GeoPoint used in loopback 3

[frbuceta]

This is a temporary solution, you have to look for a better option

Checklist

• DCO (Developer Certificate of Origin) signed in all commits
• 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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[bajtos]

Thank you @frbuceta for the pull request! ❤️

I'd like to share few pointers and some information for better context.

In the past, we have been discussing GeoPoint support in LB4 here: #1981, you may find useful information and additional pointers there.

We also have a package loopback-datatype-geopoint which adds helpers like distanceBetween and distanceTo. IMO we should not be depending on that package from LB3 days, but we may want to introduce a similar new package (@loopback/geopoint?) by migrating loopback-datatype-geopoint to TypeScript and this repository.

How Geopoint works in LoopBack 3

The REST API layer supports multiple ways how to represent GeoPoint values:

• An object {lat, lng} as you are proposing, e.g. ?arg[lat]=2.5&arg[lng]=3
• An array [lat, lng] - e.g. ?arg[0]=2.5&arg[1]=3
• Google Location API format lat,lng, e.g. `arg=2.5,3

See here: https://github.com/strongloop/strong-remoting/blob/baa3a5baaae0a1a883dfbe7eddc26982ca071959/test/rest-coercion/urlencoded-geopoint.suite.js#L24-L35

Juggler (data access layer) supports the same three representations:

[lat, lng] or object or a "lat, lng" string

See here: https://github.com/strongloop/loopback-datasource-juggler/blob/cc5557bd1126058e6ee6df9baa7ecb0f51590a86/lib/geo.js#L169-L195

BTW GeoPoint is exported by loopback-datasource-juggler. It may be possible to re-export it from @loopback/repository too, although I am not sure if that's desired. For longer term, I think we should provide GeoPoint type that's decoupled from @loopback/repository and can be used independently e.g. with @loopback/rest only or perhaps with Mongoose.

[bajtos]

IIUC, your pull request is improving only the part building JSON/OpenAPI schema to understand Juggler properties defined with GeoPoint type. That's a great first step 👍

It makes me wonder though, how would you create such model? How would be the geopoint property described at TypeScript level (what type would it have)? Would you mind to add an integration-level test to show this in practice? See packages/repository-json-schema/src/__tests__/integration/build-schema.integration.ts for examples of tests building JSON schema from a full model class created using @model and @property decorators.

[stale]

This pull request has been marked stale because it has not seen activity within two months. It will be closed within 14 days of being stale unless there is new activity.

[stale]

This pull request has been closed due to continued inactivity. If you are interested in finishing the proposed changes, then feel free to re-open this pull request or open a new one.