Feature request: optional flag to type a field as Date for date-time or date formats

[josh-feldman]

I am working on a project using OpenAPI v3 and the schema contains objects which use the type string with the format date-time.

example:

SomethingWithATimestamp:
  title: SomethingWithATimestamp
  type: object
  properties:
    timestamp:
      type: string
      format: date-time
      example: "2021-03-29T17:18:30.966Z"

The Typescript output generated by openapi-typescript results in type string (as intended). But in our case having it parsed as Date would save us a lot of manual unwrapping and .toISOString() calls, as JSON.stringify will convert the dates to ISO strings for us after calling res.send().

Therefore, an optional flag to enable parsing strings with the date-time or date format as Date would be very helpful!

[josh-feldman]

It would be additionally helpful if you could specify where you want the changes to occur. For example, perhaps you want incoming data like query params to stay string, but the ability to type response body fields as Date

[drwpow]

I could see something like this being generally-useful. What do you think about a Node.js-only API, that allows you to override the types per-object? Something like:

openapiTS(mySchema, {
  // other options
  formatter((schemaObj) => {
    if (schemaObj.format === 'date-time') {
      return 'Date'; // the TypeScript “Date” type, as a string
    }
    // for all other schema objects, let openapi-typescript decide (return undefined)
  })
});

This is something that I would want the schema authors to control, so that they can manage it. Because even in your scenario, I’d argue that string is “correct” because that’s what the API is actually returning, but I can see how the ability to override it in scenarios would be helpful.

[josh-feldman]

I think that sounds like a highly flexible solution and gives users of the package a lot more control in plenty of edge-cases, mine included.

[drwpow]

Just added this at openapi-typescript@next. Also added some docs to the README. Please give it a try and see if it’s working as expected! Happy to get feedback on this before it goes out in the next release.

[drwpow]

Also as an aside, please see the comment here regarding the Node.js API. The Node.js API may change to being an async-only function. But the advantage is it could fetch & parse remote schemas. Please leave a comment there if you have thoughts on that (we could even make it be a breaking 4.0 change if desired).

[esoteloferry]

Hi @drwpow , thanks for your work : )
I have a question, can I still use custom formatter in latest openapi-fetch (0.8.2) , I receive a string type: date in frontend and want to convert string to date .