Change JsonContent to return object rather than string

[egmacke]

Description

Resolves issue #378 by allowing objects to be sent without converting to strings.

Related Issue

Issue #378

Motivation and Context

Solves the problem where some middleware expects Json objects rather than strings. Example: openapi-validator-middleware

How Has This Been Tested?

Updated unit tests.

Functionally tested by spinning up a server with various endpoints that return both Json and non-json responses.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

This change could possibly be a breaking change in downstream implementations where middleware has been configured to expect JsonResponse

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[PodaruDragos]

overall I am ok with this PR, but please find a better type for object like Record<string, unknown>

[egmacke]

@PodaruDragos thanks for the feedback. I've updated as suggested. I'd originally used object to avoid being overly opinionated, but I agree that using Record is a better solution.

[PodaruDragos]

LGTM, thanks for this

[egmacke]

@PodaruDragos thanks.
@dcavanagh What's the release cycle for this repo? Just wondering when I'll be able to make use of this as part of a released version?

[Jameskmonger]

@egmacke sorry for the delay, I will publish this as 6.4.4 when I finish work today (#390)

[Jameskmonger]

Pleased to say this is now published on npm in version 6.4.4 @egmacke