4 files changed, 40 insertions, 7 deletions

diff --git a/src/new_fields/Doc.ts b/src/new_fields/Doc.ts
index 5ae095e68..987cb2cc4 100644
--- a/src/new_fields/Doc.ts
+++ b/src/new_fields/Doc.ts
@@ -4,7 +4,7 @@ import { autoObject, SerializationHelper, Deserializable } from "../client/util/
 import { Utils } from "../Utils";
 import { DocServer } from "../client/DocServer";
 import { setter, getter, getField } from "./util";
-import { Cast, ToConstructor } from "./Types";
+import { Cast, ToConstructor, PromiseValue } from "./Types";
 
 export type FieldId = string;
 export const HandleUpdate = Symbol("HandleUpdate");
@@ -54,7 +54,8 @@ export class Doc extends RefField {
         return doc;
     }
 
-    [key: string]: Field | FieldWaiting | undefined;
+    proto: FieldResult<Doc>;
+    [key: string]: FieldResult;
 
     @serializable(alias("fields", map(autoObject())))
     @observable
@@ -92,6 +93,32 @@ export namespace Doc {
             proto[key] = value;
         }
     }
+    export function assign<K extends string>(doc: Doc, fields: Partial<Record<K, Opt<Field>>>) {
+        for (const key in fields) {
+            if (fields.hasOwnProperty(key)) {
+                const value = fields[key];
+                if (value !== undefined) {
+                    doc[key] = value;
+                }
+            }
+        }
+        return doc;
+    }
+
+    export function MakeAlias(doc: Doc) {
+        const alias = new Doc;
+
+        PromiseValue(Cast(doc.proto, Doc)).then(proto => {
+            if (proto) {
+                alias.proto = proto;
+            }
+        });
+
+        return alias;
+    }
+
+    export function MakeDelegate(doc: Doc): Doc;
+    export function MakeDelegate(doc: Opt<Doc>): Opt<Doc>;
     export function MakeDelegate(doc: Opt<Doc>): Opt<Doc> {
         if (!doc) {
             return undefined;
diff --git a/src/new_fields/List.ts b/src/new_fields/List.ts
index f3ec9e2c5..f01ac210a 100644
--- a/src/new_fields/List.ts
+++ b/src/new_fields/List.ts
@@ -33,4 +33,4 @@ class ListImpl<T extends Field> extends ObjectField {
     private [Self] = this;
 }
 export type List<T extends Field> = ListImpl<T> & T[];
-export const List: { new <T extends Field>(): List<T> } = ListImpl as any;
\ No newline at end of file
+export const List: { new <T extends Field>(fields?: T[]): List<T> } = ListImpl as any;
\ No newline at end of file
diff --git a/src/new_fields/Types.ts b/src/new_fields/Types.ts
index 246b0624e..55083765a 100644
--- a/src/new_fields/Types.ts
+++ b/src/new_fields/Types.ts
@@ -68,7 +68,7 @@ export function FieldValue<T extends Field>(field: Opt<T> | Promise<Opt<T>>, def
 }
 
 export interface PromiseLike<T> {
-    then(callback: (field: Opt<T> | PromiseLike<T>) => void): void;
+    then(callback: (field: Opt<T>) => void): void;
 }
 export function PromiseValue<T extends Field>(field: FieldResult<T>): PromiseLike<Opt<T>> {
     return field instanceof Promise ? field : { then(cb: ((field: Opt<T>) => void)) { return cb(field); } };
diff --git a/src/new_fields/util.ts b/src/new_fields/util.ts
index 3806044bd..2d9721b2e 100644
--- a/src/new_fields/util.ts
+++ b/src/new_fields/util.ts
@@ -2,6 +2,7 @@ import { UndoManager } from "../client/util/UndoManager";
 import { Update, OnUpdate, Parent, ObjectField, RefField, Doc, Id, Field } from "./Doc";
 import { SerializationHelper } from "../client/util/SerializationHelper";
 import { ProxyField } from "./Proxy";
+import { FieldValue } from "./Types";
 
 export function setter(target: any, prop: string | symbol | number, value: any, receiver: any): boolean {
     if (SerializationHelper.IsSerializing()) {
@@ -61,11 +62,16 @@ export function getField(target: any, prop: string | number, ignoreProto: boolea
         return field.value(callback);
     }
     if (field === undefined && !ignoreProto) {
-        const proto = getField(target, "prototype", true);
+        const proto = getField(target, "proto", true);
         if (proto instanceof Doc) {
             let field = proto[prop];
-            callback && callback(field === null ? undefined : field);
-            return field;
+            if (field instanceof Promise) {
+                callback && field.then(callback);
+                return undefined;
+            } else {
+                callback && callback(field);
+                return field;
+            }
         }
     }
     callback && callback(field);