HarmonyOS Web如何实现清除缓存

import web_webview from '@ohos.web.webview'; 
import emitter from '@ohos.events.emitter'; 
 
class Clear { 
  constructor() { 
  } 
 
  clearCache() { 
    console.log("clear") 
    emitter.emit("clear"); 
  } 
} 
 
 
@Entry 
@Component 
struct WebImg { 
  webviewController: web_webview.WebviewController = new web_webview.WebviewController(); 
  clear = new Clear() 
 
  aboutToAppear(): void { 
    emitter.on("clear", () => { 
      this.clearCacheWithRomAndRam() 
    }); 
  } 
 
  clearCacheWithRomAndRam() { 
    this.webviewController.removeCache(true) 
    this.webviewController.zoomIn() 
  } 
 
  build() { 
    Column() { 
      // web组件加载本地index.html页面 
      Web({ src:$rawfile('index.html'), controller: this.webviewController })// 将对象注入到web端 
        .javaScriptProxy({ 
          object: this.clear, 
          name: "Clear", 
          methodList: ["clearCache"], 
          controller: this.webviewController 
        }) 
    } 
  } 
}