Unparse method

[yudinmaxim]

Hi everyone.

I want to do the following:

Get data from the API - perform data parsing using safeParce(schema, data) - validate and transform the data - get data with camelCase names. (This is already implemented and works well and I like it)
Create/modify form data received from the API and send the values back.
I understand how to convert data: api - valibot parse - data, but I don't understand how to do the reverse conversion: data - valibot - API.

So, I want the schema to be able to transform data not only from API - data, but also in the opposite direction.

For example, if I perform a field name transformation during data validation: field_name -> fieldName, then when performing data transfer to the API, I need to make the reverse transformation: fieldName -> field_name.

Does valibot have the ability to perform such transformations?

export const presetSchema = object({
  id: string([
    minLength(1),
  ]),
  parentId: optional(string()), // in API this field name is 'parent_id'
  params: object({
    audio: optional(number()),
    prefix: optional(string()),
    volte: optional(boolean())
  })
})
export type tPreset = Output<typeof presetSchema>

export const presetsSchema = coerce(
  array(presetSchema),
  (input: any): tPreset => {
    const output = {
      ...input,
      parentId: input.parent_id
    }
    delete output.parentId
    return output
  }
)```

[fabian-hiller]

Thank you for creating this discussion. Unfortunately, this is not supported at this time. Also, I have no idea how we could support this with a nice DX. Feel free to make suggestions. As a workaround, I would create two schemas. One for each direction.

[yudinmaxim]

Thank you for responce.
My solution is as follows.

https://stackblitz.com/edit/typescript-5yjee6?file=index.ts

Yes, two schemes are used, which looks reasonable:

1. Scheme for validating data received from the API
2. Scheme for validating data sent to the API

I'm not sure about the pick solution - it's confusing that you have to manually specify a list of required fields - but I haven't found any other solution.
If there are any suggestions, I would be very happy.

[fabian-hiller]

I think you should replace coerce with transform. You can read more about both methods here. Also the use of pick and merge seams to be unnecessary in this use case. pick is similar to Pick in TypeScript.

[yudinmaxim]

Thanks for the feedback.
I realized that I should rethink this decision and the logic of working with validators in general a few more times))
Thank you very much for your help in this matter.