fix: eval (#3877)

packages/web/src/ts/eval.ts

@@ -4,16 +4,24 @@ import {
   WeakDioxusChannel,
 } from "../../../document/src/ts/eval";
 
+window.__nextChannelId = 0;
+window.__channels = [];
+
 export class WebDioxusChannel extends DioxusChannel {
   js_to_rust: Channel;
   rust_to_js: Channel;
   owner: any;
+  id: number;
 
   constructor(owner: any) {
     super();
     this.owner = owner;
     this.js_to_rust = new Channel();
     this.rust_to_js = new Channel();
+
+    this.id = window.__nextChannelId;
+    window.__channels[this.id] = this;
+    window.__nextChannelId += 1;
   }
 
   // Return a weak reference to this channel
@@ -40,4 +48,9 @@ export class WebDioxusChannel extends DioxusChannel {
   async rustRecv(): Promise<any> {
     return await this.js_to_rust.recv();
   }
+
+  // Close the channel, dropping it.
+  close(): void {
+    window.__channels[this.id] = null;
+  }
 }