1 files changed, 12 insertions, 4 deletions
diff --git a/src/new_fields/Types.ts b/src/new_fields/Types.ts
index 4b4c58eb8..8dd893aa4 100644
--- a/src/new_fields/Types.ts
+++ b/src/new_fields/Types.ts
@@ -2,14 +2,16 @@ import { Field, Opt, FieldResult, Doc } from "./Doc";
 import { List } from "./List";
 import { RefField } from "./RefField";
 
-export type ToType<T extends ToConstructor<Field> | ListSpec<Field>> =
+export type ToType<T extends InterfaceValue> =
     T extends "string" ? string :
     T extends "number" ? number :
     T extends "boolean" ? boolean :
     T extends ListSpec<infer U> ? List<U> :
     // T extends { new(...args: any[]): infer R } ? (R | Promise<R>) : never;
+    T extends DefaultFieldConstructor<infer _U> ? never :
     T extends { new(...args: any[]): List<Field> } ? never :
-    T extends { new(...args: any[]): infer R } ? R : never;
+    T extends { new(...args: any[]): infer R } ? R :
+    T extends (doc?: Doc) => infer R ? R : never;
 
 export type ToConstructor<T extends Field> =
     T extends string ? "string" :
@@ -19,12 +21,17 @@ export type ToConstructor<T extends Field> =
     new (...args: any[]) => T;
 
 export type ToInterface<T extends Interface> = {
-    [P in Exclude<keyof T, "proto">]: FieldResult<ToType<T[P]>>;
+    [P in Exclude<keyof T, "proto">]: T[P] extends DefaultFieldConstructor<infer F> ? Exclude<FieldResult<F>, undefined> : FieldResult<ToType<T[P]>>;
 };
 
 // type ListSpec<T extends Field[]> = { List: ToContructor<Head<T>> | ListSpec<Tail<T>> };
 export type ListSpec<T extends Field> = { List: ToConstructor<T> };
 
+export type DefaultFieldConstructor<T extends Field> = {
+    type: ToConstructor<T>,
+    defaultVal: T
+};
+
 // type ListType<U extends Field[]> = { 0: List<ListType<Tail<U>>>, 1: ToType<Head<U>> }[HasTail<U> extends true ? 0 : 1];
 
 export type Head<T extends any[]> = T extends [any, ...any[]] ? T[0] : never;
@@ -32,9 +39,10 @@ export type Tail<T extends any[]> =
     ((...t: T) => any) extends ((_: any, ...tail: infer TT) => any) ? TT : [];
 export type HasTail<T extends any[]> = T extends ([] | [any]) ? false : true;
 
+export type InterfaceValue = ToConstructor<Field> | ListSpec<Field> | DefaultFieldConstructor<Field> | ((doc?: Doc) => any);
 //TODO Allow you to optionally specify default values for schemas, which should then make that field not be partial
 export interface Interface {
-    [key: string]: ToConstructor<Field> | ListSpec<Field>;
+    [key: string]: InterfaceValue;
     // [key: string]: ToConstructor<Field> | ListSpec<Field[]>;
 }