Incompatible type expected for object schemas nested in strict object schemas

[bryandrenner]

Context

• node version: 14.19.1
• module version with issue: 17.5.0, 17.6.0
• last module version without issue: 17.4.3
• environment (e.g. node, browser, native): Node
• used with (e.g. hapi application, another framework, standalone, ...): standalone

What are you trying to achieve or the steps to reproduce?

When I nest an object schema inside of another, strict object schema, I expect no type issues. For example, the following code compiles in v17.4.3:

import Joi from 'joi'

type Name = {
    first: string
    last: string
}

const nameSchema = Joi.object<Name>({
    first: Joi.string().required(),
    last: Joi.string().required()
})

type Customer = {
    name: Name
}

const customerSchema = Joi.object<Customer, true>({
    name: nameSchema
})

What was the result you got?

As of v17.5.0, the above code does not compile. The compiler reports the following:

demo.ts:18:5 - error TS2322: Type 'ObjectSchema<Name>' is not assignable to type 'ObjectSchema<StrictSchemaMap<Name>>'.
  Types of property 'concat' are incompatible.
    Type '(schema: ObjectSchema<Name>) => ObjectSchema<Name>' is not assignable to type '(schema: ObjectSchema<StrictSchemaMap<Name>>) => ObjectSchema<StrictSchemaMap<Name>>'.
      Types of parameters 'schema' and 'schema' are incompatible.
        Type 'ObjectSchema<StrictSchemaMap<Name>>' is not assignable to type 'ObjectSchema<Name>'.
          The types returned by 'validate(...)' are incompatible between these types.
            Type 'ValidationResult<StrictSchemaMap<Name>>' is not assignable to type 'ValidationResult<Name>'.
              Type '{ error: undefined; warning?: ValidationError | undefined; value: StrictSchemaMap<Name>; }' is not assignable to type 'ValidationResult<Name>'.
                Type '{ error: undefined; warning?: ValidationError | undefined; value: StrictSchemaMap<Name>; }' is not assignable to type '{ error: undefined; warning?: ValidationError | undefined; value: Name; }'.
                  Types of property 'value' are incompatible.
                    Type 'StrictSchemaMap<Name>' is not assignable to type 'Name'.

18     name: nameSchema

What result did you expect?

I would expect the code to compile without issues.

If I change this line:

const customerSchema = Joi.object<Customer, true>({

...to this:

const customerSchema = Joi.object<Customer>({

...then the code compiles, but I lose the safety of strict object schemas.

[dunyakirkali]

I have the same issue

It used to work in 17.4.2 but stoped working in 17.6.0

Just by looking at the changelog I don't see what might have caused the issue

[vdvleon]

I am experiencing the same problem. It seems the return type of joi.object<Type, true>() returns an ObjectSchema without the strict typing applied on its generic type.

[LeoAso]

The issue comes from #2627.

That PR added isStrict to Joi.object, but then requires that any schema nested inside a strict schema must have the type ObjectSchema<StrictSchemaMap<T>>, which isn't possible because Joi.object returns ObjectSchema<T> whether it is strict or not. Even the example given in the PR doesn't work anymore with those changes.

I think I'll open a new PR to fix the issue.

[matgott]

Hi folks! I see two PRs open to fix this issue.

Is there any ETA for this? Thank you