Preflight validation check failed to guard for the given schema when using `structuredClone`

[cmcnicholas]

When using structuredClone on typebox models I experience "Preflight validation check failed to guard for the given schema".

This does not happen when simply destructuring a typbox model. e.g.

import { Type } from "@sinclair/typebox";
import { TypeCompiler } from "@sinclair/typebox/compiler";

// database model
const LettersDbModel = Type.Any([Type.Literal("A"), Type.Literal("B")]);

// a web model we want to expose, derived from db model (in this case they are identical)
const LettersWebModel = structuredClone(LettersDbModel);
// const LettersWebModel = { ...LettersDbModel }; // this works?

// a web model we want to expose
const SomeWebModel = Type.Object({
  letter: LettersWebModel,
});

// this line fails when using structuredClone
const SomeWebModelCompiled = TypeCompiler.Compile(SomeWebModel);

console.log(
  "should be false",
  SomeWebModelCompiled.Check({
    letter: "C",
  })
);
console.log(
  "should be true",
  SomeWebModelCompiled.Check({
    letter: "B",
  })
);

My use case is I want to reuse model definitions, potentially enhancing or changing properties as such $id etc. without risk of referencing the originating object. I know destructuring should work but structuredClone feels like a neater solution to make sure changes are isolated.

[sinclairzx81]

@cmcnicholas Hi,

Unfortunately, structuredClone won't clone the Symbol properties TypeBox uses to compose, compile and check types. However you can use TypeBox's CloneType function to perform a deep clone of a type.

import { Type, CloneType } from "@sinclair/typebox"; // added
import { TypeCompiler } from "@sinclair/typebox/compiler";

// database model
const LettersDbModel = Type.Any([Type.Literal("A"), Type.Literal("B")]);

// a web model we want to expose, derived from db model (in this case they are identical)
const LettersWebModel = CloneType(LettersDbModel);
// const LettersWebModel = { ...LettersDbModel }; // this works?
console.log(LettersWebModel)

// a web model we want to expose
const SomeWebModel = Type.Object({
  letter: LettersWebModel,
});

// UPDATE: This line should succeed as the compositing symbols are preserved
const SomeWebModelCompiled = TypeCompiler.Compile(SomeWebModel);

console.log(
  "should be false",
  SomeWebModelCompiled.Check({
    letter: "C",
  })
);
console.log(
  "should be true",
  SomeWebModelCompiled.Check({
    letter: "B",
  })
);

Also as an aside, it looks like the LettersDbModel may be incorrect...

const LettersDbModel = Type.Any([Type.Literal("A"), Type.Literal("B")]);

// did you mean?

const LettersDbModel = Type.Union([Type.Literal("A"), Type.Literal("B")]); ??

Hope this helps S

[cmcnicholas]

@cmcnicholas Hi,

Unfortunately, structuredClone won't clone the Symbol properties TypeBox uses to compose, compile and check types. However you can use TypeBox's CloneType function to perform a deep clone of a type.

import { Type, CloneType } from "@sinclair/typebox"; // added
import { TypeCompiler } from "@sinclair/typebox/compiler";

// database model
const LettersDbModel = Type.Any([Type.Literal("A"), Type.Literal("B")]);

// a web model we want to expose, derived from db model (in this case they are identical)
const LettersWebModel = CloneType(LettersDbModel);
// const LettersWebModel = { ...LettersDbModel }; // this works?
console.log(LettersWebModel)

// a web model we want to expose
const SomeWebModel = Type.Object({
  letter: LettersWebModel,
});

// UPDATE: This line should succeed as the compositing symbols are preserved
const SomeWebModelCompiled = TypeCompiler.Compile(SomeWebModel);

console.log(
  "should be false",
  SomeWebModelCompiled.Check({
    letter: "C",
  })
);
console.log(
  "should be true",
  SomeWebModelCompiled.Check({
    letter: "B",
  })
);

Also as an aside, it looks like the LettersDbModel may be incorrect...

const LettersDbModel = Type.Any([Type.Literal("A"), Type.Literal("B")]);

// did you mean?

const LettersDbModel = Type.Union([Type.Literal("A"), Type.Literal("B")]); ??

Hope this helps S

I did thanks, my code is using it correctly was just my repro was rubbish :P

CloneType absolutely works for me 👍