fix(schema): preserve array element inference#46
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Reorder ArraySchema overloads specific-before-broad so that
TypeGuard/ValidatorMap/StandardSchemaV1 overloads match before the
catch-all (tree: {}) overload. Same reorder in _fn and OptionalizedArray.
Closes #39
Cover array(string()).optional() (known: |undefined dropped), asEnum literal union inference, and custom TypeGuard inference.
This was referenced May 27, 2026
Infer<T> correctly preserves | undefined for FluentOptionalSchema. Previous test asserted the broken behavior (string[] instead of string[] | undefined) based on misleading TypeScript error messages. Closes #48
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Summary
Fixes #39 —
Infer<typeof array(schema)>now correctly resolves to the element type array (e.g.string[]) instead of{}[].Root Cause
The
(tree: {})overload inArraySchemawas positioned before the generic<T>(tree: ValidatorMap<T> | TypeGuard<T> | StandardSchemaV1<T, T>)overload. SinceFluentSchema<T>extends{}, TypeScript always matched the broad(tree: {})overload first, losing the element type.Changes
src/validators/schema/types/ArraySchema.ts: Reorder overloads — generic overload before(tree: {})catch-allsrc/validators/schema/array.ts: Same reorder in_fnandOptionalizedArraytype overloadssrc/validators/__tests__/array.spec.ts: New test file with type inference assertions and runtime regression checksVerified Inference
Infer<typeof array(string())>{}[]string[]Infer<typeof array(object({ id: string() }))>{}[]{ id: string }[]Infer<typeof array({ id: string() })>{ id: StringSchema }[]{ id: string }[]Infer<typeof array(zodStdSchema)>{}[]string[]Infer<typeof array()>unknown[]any[]No runtime behavior changes — only type-level resolution is affected.
Test Plan
yarn tsc -p tsconfig.json --noEmitpassesyarn tsc -p tsconfig.cjs.json --noEmitpassesyarn buildsucceeds