snapshot of https://github.com/toeverything/AFFiNE.git (canary, 2026-09-16; blobs > 131072B omitted)

blocksuite/framework/std/src/event/base.ts

@@ -0,0 +1,62 @@
+import { BlockSuiteError, ErrorCode } from '@blocksuite/global/exceptions';
+
+type MatchEvent<T extends string> = T extends UIEventStateType
+  ? BlockSuiteUIEventState[T]
+  : UIEventState;
+
+export class UIEventState {
+  /** when extends, override it with pattern `xxxState` */
+  type = 'defaultState';
+
+  constructor(public event: Event) {}
+}
+
+export class UIEventStateContext {
+  private _map: Record<string, UIEventState> = {};
+
+  add = <State extends UIEventState = UIEventState>(state: State) => {
+    const name = state.type;
+    if (this._map[name]) {
+      console.warn('UIEventStateContext: state name duplicated', name);
+    }
+
+    this._map[name] = state;
+  };
+
+  get = <Type extends UIEventStateType = UIEventStateType>(
+    type: Type
+  ): MatchEvent<Type> => {
+    const state = this._map[type];
+    if (!state) {
+      throw new BlockSuiteError(
+        ErrorCode.EventDispatcherError,
+        `UIEventStateContext: state ${type} not found`
+      );
+    }
+    return state as MatchEvent<Type>;
+  };
+
+  has = (type: UIEventStateType) => {
+    return !!this._map[type];
+  };
+
+  static from(...states: UIEventState[]) {
+    const context = new UIEventStateContext();
+    states.forEach(state => {
+      context.add(state);
+    });
+    return context;
+  }
+}
+
+export type UIEventHandler = (
+  context: UIEventStateContext
+) => boolean | null | undefined | void;
+
+declare global {
+  interface BlockSuiteUIEventState {
+    defaultState: UIEventState;
+  }
+
+  type UIEventStateType = keyof BlockSuiteUIEventState;
+}