@studnicky/interfaces-compose-named-types

Disallows inline object literal types (TSTypeLiteral) anywhere inside an interface body — property types, method return types, and index signature value types. Interfaces must compose by referencing named types: extract the inline shape to an entity (export namespace XxxEntity { Schema, Type, validate }) and reference its Type instead. A bare type alias is not a valid extraction target, since free-standing type aliases are separately forbidden outside entities. Generic type-parameter constraints (interface Foo<T extends { a: number }>) are exempt, since the object literal there constrains a parameter rather than shaping a member.

Fixable: No · Options: No · Suggested severity: error

✗ Incorrect

// inline object property type inside an interface
interface Foo { bar: { a: number }; }

// method signature returning an inline object type
interface Foo { method(): { a: number }; }

// index signature with an inline object value type
interface Foo { [key: string]: { a: number }; }

✓ Correct

// references a named type instead of an inline shape
interface Foo { bar: BarType; }

// generic type-parameter constraint — exempt, not a member shape
interface Foo<T extends { a: number }> { bar: T; }

// method signature with no inline object literal
interface Foo { greet(): void; }