Read parent object in custom tag

[sergio-milu]

Hi, I'm trying to read the parent object (input) in a custom validation tag.

I think I found a workaround for it, using input without the $ as prefix, but this works right now, maybe not in the future if you change that variable name. Is this possible right now? I think this is useful, maybe the validate callback could receive the parent object as arg.

Current

type TestFeature<
  Value extends 'test'
> = typia.tags.TagBase<{
  kind: 'hasEHRFeature';
  target: 'string';
  value: Value;
  validate: `(function () {
  const hasFeature = require('@utils').hasFeature;
  return hasFeature(input.system, '${Value}') && typeof $input === 'string'
})()`;
}>; 

Proposal

type TestFeature<
  Value extends 'test'
> = typia.tags.TagBase<{
  kind: 'hasEHRFeature';
  target: 'string';
  value: Value;
  validate: `(function (input /* AS ARG HERE */ ) {
  const hasFeature = require('@utils').hasFeature;
  return hasFeature(input.system, '${Value}') && typeof $input === 'string'
})()`;
}>; 

thanks

[samchon]

Not possible to get parent object info.

If it requires, it is out of validation library scope.

[sergio-milu]

Not possible to get parent object info.

If it requires, it is out of validation library scope.

well, actually it is possible, because that code is working and I'm reading parent object info.

I'm asking this cause this feature exists in nestjs/swagger and IMO is useful, so why should it be out of the scope of the validation library something that is working right now (even is not documented) and is useful for validation purposes (validate some field based on another field)?

[samchon]

The parent object, it is just your domestic issue. The parent can be sometimes array, sometimes tuple, and even possible to does not exist due to standalone utilization.

I do not have plan to support such private and type unsafe story. If you need to solve your domain problem, then you have to do it by yourself.

[samchon]

Also, the reason why you could utilize the input variable of object, it is due to transformed JS code is using the variable name for each object type. It is free that you are utilizing it, but I do not have plan to introduce it as a regular feature.

For reference, if some object type is extremely simple, it would be inlined, so that input variable may not mean the actual parent object.

• inlined case: https://github.com/samchon/typia/blob/master/test/src/generated/output/createIs/test_createIs_ObjectSimple.ts
• normal case: https://github.com/samchon/typia/blob/master/test/src/generated/output/createIs/test_createIs_ObjectRecursive.ts

[sergio-milu]

so, with typia there's no way to validate one property based in another one at same level?

interface Test {
    protocol: string;
    port: number & Protocol<'protocol'>
}

in this contrived exampled, validated that port is 443 is protocol is https, could this be achieved?

[samchon]

Not possible.

[sergio-milu]

Not possible.

and why custom tags only supports this values Target extends "bigint" | "number" | "string" | "array",?

my questions is I can use an array of objects, but not a plain object, os there any special reason behind that?

[samchon]

In the object case, it actually defined as actual property type in the compiler API.

I can separate it manually, but did not it due to no use case yet.