Allow ref blots to be null

CHANGELOG.md

@@ -1,5 +1,7 @@
 # [Unreleased]
 
+- Allow ref blots to be null
+
 # 3.0.0-rc.0
 
 - Keep identify names in built code bundle

src/blot/abstract/blot.ts

@@ -96,8 +96,8 @@ export interface Parent extends Blot {
     index: number,
     length: number,
   ): T[];
-  insertBefore(child: Blot, refNode?: Blot): void;
-  moveChildren(parent: Parent, refNode?: Blot): void;
+  insertBefore(child: Blot, refNode?: Blot | null): void;
+  moveChildren(parent: Parent, refNode?: Blot | null): void;
   path(index: number, inclusive?: boolean): [Blot, number][];
   removeChild(child: Blot): void;
   unwrap(): void;

src/blot/abstract/parent.ts

@@ -243,7 +243,7 @@ class ParentBlot extends ShadowBlot implements Parent {
     }, 0);
   }
 
-  public moveChildren(targetParent: Parent, refNode?: Blot): void {
+  public moveChildren(targetParent: Parent, refNode?: Blot | null): void {
     this.children.forEach((child) => {
       targetParent.insertBefore(child, refNode);
     });