feat: add type check for compatible

src/living/nodes/Node.test.ts

@@ -0,0 +1,8 @@
+import type { CheckStrictCompatible, Equal, Expect } from "../../type.test";
+import { NodeImpl } from './Node';
+
+type IncompatibleFields = CheckStrictCompatible<Node, NodeImpl>;
+
+type cases = [
+  Expect<Equal<{}, IncompatibleFields>>,
+];

src/living/nodes/Node.ts

@@ -214,7 +214,7 @@ export class NodeImpl extends EventTarget implements Node {
     return documentBaseURLSerialized(this._ownerDocument);
   }
 
-  get parentNode(): ParentNodeImpl {
+  get parentNode(): ParentNode {
     return domSymbolTree.parent(this);
   }
 
@@ -275,15 +275,15 @@ export class NodeImpl extends EventTarget implements Node {
     return this.nodeType === this.DOCUMENT_NODE ? null : this._ownerDocument as Document;
   }
 
-  get nextSibling() {
+  get nextSibling(): ChildNode | null {
     return domSymbolTree.nextSibling(this);
   }
 
-  get previousSibling() {
+  get previousSibling(): ChildNode | null {
     return domSymbolTree.previousSibling(this);
   }
 
-  get parentElement() {
+  get parentElement(): HTMLElement | null {
     const parentNode = domSymbolTree.parent(this);
     return parentNode !== null && parentNode.nodeType === NodeImpl.ELEMENT_NODE ? parentNode : null;
   }
@@ -509,8 +509,9 @@ export class NodeImpl extends EventTarget implements Node {
   removeChild<T extends Node>(child: T): T {
     return this._preRemove(child as unknown as NodeImpl) as unknown as T;
   }
-  replaceChild<T1 extends Node, T2 extends Node>(node: T1, child: T1): T2 {
-    return this._replace(node as unknown as NodeImpl, child as unknown as NodeImpl) as unknown as T2;
+
+  replaceChild<T extends Node>(node: Node, child: T): T {
+    return this._replace(node as unknown as NodeImpl, child as unknown as NodeImpl) as unknown as T;
   }
 
   // https://dom.spec.whatwg.org/#concept-node-ensure-pre-insertion-validity

src/type.utils.d.ts

@@ -0,0 +1,12 @@
+export type Equal<X, Y> =
+  (<T>() => T extends X ? 1 : 2) extends
+  (<T>() => T extends Y ? 1 : 2) ? true : false;
+
+export type NotEqual<X, Y> = true extends Equal<X, Y> ? false : true;
+export type Expect<T extends true> = T;
+
+export type FindValidFields<T> = {
+  [K in keyof T]: T[K] extends never ? never : K;
+}[keyof T];
+
+export type CheckStrictCompatible<StandardType, ImplType extends StandardType, Checked = {[k in keyof StandardType]: Equal<StandardType[k], ImplType[k]> extends true ? never : [StandardType[k], ImplType[k]]}> = Pick<Checked, FindValidFields<Checked>>;