dont use instanceof

packages/core/src/Extension.ts

@@ -65,6 +65,8 @@ export interface ExtensionConfig<Options = any, Commands = {}> {
 }
 
 export class Extension<Options = any, Commands = any> {
+  type = 'extension'
+
   config: Required<ExtensionConfig> = {
     name: 'extension',
     defaultOptions: {},

packages/core/src/Mark.ts

@@ -111,6 +111,8 @@ export interface MarkConfig<Options = any, Commands = {}> extends Overwrite<Exte
 }> {}
 
 export class Mark<Options = any, Commands = {}> {
+  type = 'mark'
+
   config: Required<MarkConfig> = {
     name: 'mark',
     defaultOptions: {},

packages/core/src/Node.ts

@@ -155,6 +155,8 @@ export interface NodeConfig<Options = any, Commands = {}> extends Overwrite<Exte
 }> {}
 
 export class Node<Options = any, Commands = {}> {
+  type = 'node'
+
   config: Required<NodeConfig> = {
     name: 'node',
     defaultOptions: {},

packages/core/src/utils/splitExtensions.ts

@@ -4,9 +4,9 @@ import { Node } from '../Node'
 import { Mark } from '../Mark'
 
 export default function splitExtensions(extensions: Extensions) {
-  const baseExtensions = extensions.filter(extension => extension instanceof Extension) as Extension[]
-  const nodeExtensions = extensions.filter(extension => extension instanceof Node) as Node[]
-  const markExtensions = extensions.filter(extension => extension instanceof Mark) as Mark[]
+  const baseExtensions = extensions.filter(extension => extension.type === 'extension') as Extension[]
+  const nodeExtensions = extensions.filter(extension => extension.type === 'node') as Node[]
+  const markExtensions = extensions.filter(extension => extension.type === 'mark') as Mark[]
 
   return {
     baseExtensions,