Angular 7 - HTML5 全屏 API 如何工作？我有很多错误

Question

我使用 Angular 7，我希望有一个按钮可以将我的应用程序置于全屏模式。我使用 HTML5 Fullscreen API 并且创建了 2 个函数:

openfullscreen() {
    // Trigger fullscreen
    console.log('gg');
    if (document.documentElement.requestFullscreen) {
      document.documentElement.requestFullscreen();
    } else if (document.documentElement.mozRequestFullScreen) { /* Firefox */
      document.documentElement.mozRequestFullScreen();
    } else if (document.documentElement.webkitRequestFullscreen) { /* Chrome, Safari and Opera */
      document.documentElement.webkitRequestFullscreen();
    } else if (document.documentElement.msRequestFullscreen) { /* IE/Edge */
      document.documentElement.msRequestFullscreen();
    }
    this.isfullscreen = true;
  }

  closefullscreen(){
    if (document.exitFullscreen) {
      document.exitFullscreen();
    } else if (document.mozCancelFullScreen) { /* Firefox */
      document.mozCancelFullScreen();
    } else if (document.webkitExitFullscreen) { /* Chrome, Safari and Opera */
      document.webkitExitFullscreen();
    } else if (document.msExitFullscreen) { /* IE/Edge */
      document.msExitFullscreen();
    }
    this.isfullscreen = false;
  }

一开始它有效，但我遇到了很多错误:

error TS2339: Property 'mozRequestFullScreen' does not exist on type 'HTMLElement'.

error TS2339: Property 'mozRequestFullScreen' does not exist on type 'HTMLElement'.

error TS2339: Property 'webkitRequestFullscreen' does not exist on type 'HTMLElement'.

error TS2339: Property 'webkitRequestFullscreen' does not exist on type 'HTMLElement'.

error TS2551: Property 'msRequestFullscreen' does not exist on type 'HTMLElement'. Did you mean 'requestFullscreen'?

error TS2551: Property 'msRequestFullscreen' does not exist on type 'HTMLElement'. Did you mean 'requestFullscreen'?

error TS2339: Property 'mozCancelFullScreen' does not exist on type 'Document'.

error TS2339: Property 'mozCancelFullScreen' does not exist on type 'Document'.

error TS2339: Property 'webkitExitFullscreen' does not exist on type 'Document'.

error TS2339: Property 'webkitExitFullscreen' does not exist on type 'Document'.

error TS2551: Property 'msExitFullscreen' does not exist on type 'Document'. Did you mean 'exitFullscreen'?

error TS2551: Property 'msExitFullscreen' does not exist on type 'Document'. Did you mean 'exitFullscreen'?

当我重新启动代码时，我遇到了同样的错误，但除此之外，我还有:

Failed to compile.

我的应用程序无法运行。如何编译才不会出错？

Answer 1

您可以通过使用 as 关键字来转换 document 和 document.documentElement< 的接口(interface)，告诉 typescript 您将要使用的方法.

像这样:

const docElmWithBrowsersFullScreenFunctions = document.documentElement as HTMLElement & {
  mozRequestFullScreen(): Promise<void>;
  webkitRequestFullscreen(): Promise<void>;
  msRequestFullscreen(): Promise<void>;
};

const docWithBrowsersExitFunctions = document as Document & {
  mozCancelFullScreen(): Promise<void>;
  webkitExitFullscreen(): Promise<void>;
  msExitFullscreen(): Promise<void>;
};

请注意，这只是防止编译错误，您仍然应该像您一样检查方法是否存在。

所以你的方法将是这样的:

openfullscreen() {
  // Trigger fullscreen
  const docElmWithBrowsersFullScreenFunctions = document.documentElement as HTMLElement & {
    mozRequestFullScreen(): Promise<void>;
    webkitRequestFullscreen(): Promise<void>;
    msRequestFullscreen(): Promise<void>;
  };

  if (docElmWithBrowsersFullScreenFunctions.requestFullscreen) {
    docElmWithBrowsersFullScreenFunctions.requestFullscreen();
  } else if (docElmWithBrowsersFullScreenFunctions.mozRequestFullScreen) { /* Firefox */
    docElmWithBrowsersFullScreenFunctions.mozRequestFullScreen();
  } else if (docElmWithBrowsersFullScreenFunctions.webkitRequestFullscreen) { /* Chrome, Safari and Opera */
    docElmWithBrowsersFullScreenFunctions.webkitRequestFullscreen();
  } else if (docElmWithBrowsersFullScreenFunctions.msRequestFullscreen) { /* IE/Edge */
    docElmWithBrowsersFullScreenFunctions.msRequestFullscreen();
  }
  this.isfullscreen = true;
}

closefullscreen(){
  const docWithBrowsersExitFunctions = document as Document & {
    mozCancelFullScreen(): Promise<void>;
    webkitExitFullscreen(): Promise<void>;
    msExitFullscreen(): Promise<void>;
  };
  if (docWithBrowsersExitFunctions.exitFullscreen) {
    docWithBrowsersExitFunctions.exitFullscreen();
  } else if (docWithBrowsersExitFunctions.mozCancelFullScreen) { /* Firefox */
    docWithBrowsersExitFunctions.mozCancelFullScreen();
  } else if (docWithBrowsersExitFunctions.webkitExitFullscreen) { /* Chrome, Safari and Opera */
    docWithBrowsersExitFunctions.webkitExitFullscreen();
  } else if (docWithBrowsersExitFunctions.msExitFullscreen) { /* IE/Edge */
    docWithBrowsersExitFunctions.msExitFullscreen();
  }
  this.isfullscreen = false;
}