fix: RecursiveFormFields type for recursive or unknown schemas (#14734)

* fix: `RecursiveFormFields` type for recursive or unknown schemas * fix: better recursive unknown fields * simplify type

Author: sillvva

.changeset/upset-hotels-mix.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: `RecursiveFormFields` type for recursive or unknown schemas

packages/kit/src/exports/public.d.ts

@@ -1914,22 +1914,46 @@ type RemoteFormFieldContainer<Value> = RemoteFormFieldMethods<Value> & {
 allIssues(): RemoteFormIssue[] | undefined;
 };
 
+type UnknownField<Value> = RemoteFormFieldMethods<Value> & {
+/** Validation issues belonging to this or any of the fields that belong to it, if any */
+allIssues(): RemoteFormIssue[] | undefined;
+/**
+ * Returns an object that can be spread onto an input element with the correct type attribute,
+ * aria-invalid attribute if the field is invalid, and appropriate value/checked property getters/setters.
+ * @example
+ * ```svelte
+ * <input {...myForm.fields.myString.as('text')} />
+ * <input {...myForm.fields.myNumber.as('number')} />
+ * <input {...myForm.fields.myBoolean.as('checkbox')} />
+ * ```
+ */
+as<T extends RemoteFormFieldType<Value>>(...args: AsArgs<T, Value>): InputElementProps<T>;
+} & {
+[key: string | number]: UnknownField<any>;
+};
+
 /**
  * Recursive type to build form fields structure with proxy access
  */
-type RemoteFormFields<T> =
+export type RemoteFormFields<T> =
 WillRecurseIndefinitely<T> extends true
 ? RecursiveFormFields
 : NonNullable<T> extends string | number | boolean | File
 ? RemoteFormField<NonNullable<T>>
 : T extends string[] | File[]
 ? RemoteFormField<T> & { [K in number]: RemoteFormField<T[number]> }
 : T extends Array<infer U>
-? RemoteFormFieldContainer<T> & { [K in number]: RemoteFormFields<U> }
-: RemoteFormFieldContainer<T> & { [K in keyof T]-?: RemoteFormFields<T[K]> };
+? RemoteFormFieldContainer<T> & {
+[K in number]: RemoteFormFields<U>;
+}
+: RemoteFormFieldContainer<T> & {
+[K in keyof T]-?: RemoteFormFields<T[K]>;
+};
 
 // By breaking this out into its own type, we avoid the TS recursion depth limit
-type RecursiveFormFields = RemoteFormField<any> & { [key: string | number]: RecursiveFormFields };
+type RecursiveFormFields = RemoteFormFieldContainer<any> & {
+[key: string | number]: UnknownField<any>;
+};
 
 type MaybeArray<T> = T | T[];
 

packages/kit/types/index.d.ts

@@ -1890,22 +1890,46 @@ declare module '@sveltejs/kit' {
 allIssues(): RemoteFormIssue[] | undefined;
 };
 
+type UnknownField<Value> = RemoteFormFieldMethods<Value> & {
+/** Validation issues belonging to this or any of the fields that belong to it, if any */
+allIssues(): RemoteFormIssue[] | undefined;
+/**
+ * Returns an object that can be spread onto an input element with the correct type attribute,
+ * aria-invalid attribute if the field is invalid, and appropriate value/checked property getters/setters.
+ * @example
+ * ```svelte
+ * <input {...myForm.fields.myString.as('text')} />
+ * <input {...myForm.fields.myNumber.as('number')} />
+ * <input {...myForm.fields.myBoolean.as('checkbox')} />
+ * ```
+ */
+as<T extends RemoteFormFieldType<Value>>(...args: AsArgs<T, Value>): InputElementProps<T>;
+} & {
+[key: string | number]: UnknownField<any>;
+};
+
 /**
  * Recursive type to build form fields structure with proxy access
  */
-type RemoteFormFields<T> =
+export type RemoteFormFields<T> =
 WillRecurseIndefinitely<T> extends true
 ? RecursiveFormFields
 : NonNullable<T> extends string | number | boolean | File
 ? RemoteFormField<NonNullable<T>>
 : T extends string[] | File[]
 ? RemoteFormField<T> & { [K in number]: RemoteFormField<T[number]> }
 : T extends Array<infer U>
-? RemoteFormFieldContainer<T> & { [K in number]: RemoteFormFields<U> }
-: RemoteFormFieldContainer<T> & { [K in keyof T]-?: RemoteFormFields<T[K]> };
+? RemoteFormFieldContainer<T> & {
+[K in number]: RemoteFormFields<U>;
+}
+: RemoteFormFieldContainer<T> & {
+[K in keyof T]-?: RemoteFormFields<T[K]>;
+};
 
 // By breaking this out into its own type, we avoid the TS recursion depth limit
-type RecursiveFormFields = RemoteFormField<any> & { [key: string | number]: RecursiveFormFields };
+type RecursiveFormFields = RemoteFormFieldContainer<any> & {
+[key: string | number]: UnknownField<any>;
+};
 
 type MaybeArray<T> = T | T[];