feat(core): add user list service for blocksuite (#10627)

packages/common/infra/package.json

@@ -15,6 +15,7 @@
     "@affine/env": "workspace:*",
     "@affine/templates": "workspace:*",
     "@datastructures-js/binary-search-tree": "^5.3.2",
+    "@preact/signals-core": "^1.8.0",
     "eventemitter2": "^6.4.9",
     "foxact": "^0.2.43",
     "fractional-indexing": "^3.2.0",

packages/common/infra/src/livedata/livedata.ts

@@ -1,4 +1,5 @@
 import { DebugLogger } from '@affine/debug';
+import { type ReadonlySignal, type Signal, signal } from '@preact/signals-core';
 import type {
   InteropObservable,
   Observer,
@@ -140,6 +141,17 @@ export class LiveData<T = unknown>
     return data$;
   }
 
+  static fromSignal<T>(signal: ReadonlySignal<T>): LiveData<T> {
+    return LiveData.from(
+      new Observable(subscriber => {
+        signal.subscribe(value => {
+          subscriber.next(value);
+        });
+      }),
+      signal.value
+    );
+  }
+
   private static GLOBAL_COMPUTED_RECURSIVE_COUNT = 0;
 
   /**
@@ -286,6 +298,19 @@ export class LiveData<T = unknown>
     this.next(v);
   }
 
+  private _signal: Signal<T> | undefined;
+
+  get signal(): ReadonlySignal<T> {
+    if (!this._signal) {
+      this._signal = signal(this.value);
+      this.subscribe(v => {
+        // oxlint-disable-next-line no-non-null-assertion
+        this._signal!.value = v;
+      });
+    }
+    return this._signal;
+  }
+
   next = (v: T) => {
     if (this.isPoisoned) {
       throw this.poisonedError;
@@ -379,7 +404,6 @@ export class LiveData<T = unknown>
     );
   }
 
-  // eslint-disable-next-line rxjs/finnish
   asObservable(): Observable<T> {
     return new Observable<T>(subscriber => {
       return this.subscribe(subscriber);
@@ -421,7 +445,7 @@ export class LiveData<T = unknown>
   override pipe(...args: any[]) {
     return new Observable(subscriber => {
       this.ops$.next('watch');
-      // eslint-disable-next-line prefer-spread
+
       const subscription = this.raw$.pipe
         .apply(this.raw$, args as any)
         .subscribe(subscriber);