⚡️ fix the performance issue in sandbox (#1626)

src/sandbox/common.ts

@@ -5,13 +5,23 @@
 
 import { isBoundedFunction, isCallable, isConstructable } from '../utils';
 
-let currentRunningSandboxProxy: WindowProxy | null = null;
+declare global {
+  interface Window {
+    __currentRunningSandboxProxy__: WindowProxy | null;
+  }
+}
+
+// Get native global window with a sandbox disgusted way, thus we could share it between qiankun instances🤪
+// eslint-disable-next-line no-new-func
+const nativeGlobal: Window = new Function('return this')();
+Object.defineProperty(nativeGlobal, '__currentRunningSandboxProxy__', { enumerable: false, writable: true });
 export function getCurrentRunningSandboxProxy() {
-  return currentRunningSandboxProxy;
+  return nativeGlobal.__currentRunningSandboxProxy__;
 }
 
 export function setCurrentRunningSandboxProxy(proxy: WindowProxy | null) {
-  currentRunningSandboxProxy = proxy;
+  // set currentRunningSandboxProxy to global window, as its only use case is for document.createElement from now on, which hijacked by a global way
+  nativeGlobal.__currentRunningSandboxProxy__ = proxy;
 }
 
 const functionBoundedValueMap = new WeakMap<CallableFunction, CallableFunction>();

src/sandbox/proxySandbox.ts

@@ -215,14 +215,14 @@ export default class ProxySandbox implements SandBox {
       },
 
       get(target: FakeWindow, p: PropertyKey): any {
+        if (p === Symbol.unscopables) return unscopables;
+
         setCurrentRunningSandboxProxy(proxy);
         // FIXME if you have any other good ideas
         // remove the mark in next tick, thus we can identify whether it in micro app or not
         // this approach is just a workaround, it could not cover all complex cases, such as the micro app runs in the same task context with master in some case
         nextTick(() => setCurrentRunningSandboxProxy(null));
 
-        if (p === Symbol.unscopables) return unscopables;
-
         // avoid who using window.window or window.self to escape the sandbox environment to touch the really window
         // see https://github.com/eligrey/FileSaver.js/blob/master/src/FileSaver.js#L13
         if (p === 'window' || p === 'self') {