Date Object Incompatibility with json-schema-to-ts Type Generation

[mmdalix]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Fastify version

5.1.0

Plugin version

4.0.0

Node.js version

20.11.1

Operating system

macOS

Operating system version (i.e. 20.04, 11.3, 10)

24.1.0

Description

When working with fastify and its response serializer (fast-json-stringify), I noticed an inconsistency with how date objects are handled between fast-json-stringify and json-schema-to-ts.

The fast-json-stringify serializer allows me to directly provide a Date object, which is then correctly serialized to a date-time string format in the response. However, json-schema-to-ts requires the type definition to explicitly expect a string, not a Date, even though the JSON schema specifies a date-time format.

Example Schema:
response: { 200: { type: 'object', properties: { createdAt: { type: 'string', format: "date-time" }, } } }

Link to code that reproduces the bug

No response

Expected Behavior

It would be helpful if json-schema-to-ts could accommodate Date objects when a JSON schema property is set to a date-time format, matching the behavior of fast-json-stringify.

[mcollina]

I do not have an idea on how this could be achieved, but a PR that implemented this would be amazing.

[bcomnes]

I think I added support for a fix/workaround in this PR: #103

Using the deserialize type option on the serializer lets you return Date objects.

[mikaelkaron]

Wow @bcomnes - really firing on all cylinders today, this is the second issue I had with this plugin that you are fixing today.