feat/complex-x-ts-types - Adds supports for using x-ts-type in anyOf, allOf, oneOf, and not keywords

[mschnee]

Partially implements: #4300
See: #4406

This has been split from #4406 as a more manageable, smaller PR.

Added

This PR adds support for using x-ts-type schema bodies the value of anyOf, allOf, oneOf, and not schema object keys, as described by the OpenAPI Schema Object specification. In this example ResponseObject:

{
  description: 'Path Response Description',
  content: {
    'application/json': {
      schema: {
        anyOf: [
          { 'x-ts-type': CouldBeThisModel },
          { 'x-ts-type': OrThisModel } 
        ],
        not: { 'x-ts-type': ButNotThisModel }
      }
    }
  }
}

Checklist

• 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
• (n/a) Affected artifact templates in packages/cli were updated
• Affected example projects in examples/* were updated

[mschnee]

NOTE I've rebased and force-pushed my branch. I hope that addresses the travis-commitlint build errors, as I think that may have come in from pulling upstream.

[dhmlau]

FYI - the drop in test coverage is in the examples package which I don't think it's related to the changes in this PR.

[mschnee]

$ source cloudant-config.sh && npm run mocha
/home/travis/.travis/functions: line 109: cloudant-config.sh: No such file or directory

:/

I'd love a little assistance in addressing this failing test. I don't believe the changes in this PR had any impact on the cloudant tests.

[raymondfeng]

@mschnee Please ignore the cloudant issue.

[mschnee]

I will update the documentation referring to x-ts-type to be more explicit about anyOf/allOf/oneOf/not tomorrow.

[mschnee]

Document updated :)

[raymondfeng]

@mschnee Please rebase your branch to latest master to pass CI tests.

[raymondfeng]

@mschnee Please follows instructions at https://loopback.io/doc/en/lb4/submitting_a_pr.html#6-rebasing for rebasing.

[mschnee]

Rebase complete! :)

[raymondfeng]

@mschnee Thank you for cleaning up the PR. One last step - please squash two commits into one per instructions at https://loopback.io/doc/en/lb4/submitting_a_pr.html#10-final-rebase-and-squashing-of-commits.

[mschnee]

Rebased off of master this morning again and pushed :)