index.ts

export const portalViews = new Map<string, WebContentsView>()

mainWindow.webContents.setWindowOpenHandler((details) => {
    const { frameName } = details
    if (frameName && frameName.startsWith('portal:')) {
      const portalId = frameName.slice('portal:'.length)
      if (portalViews.has(portalId)) {
        return { action: 'deny' }
      }
      return {
        action: 'allow',
        createWindow: (options) => {
          const wc = (options as any).webContents as Electron.WebContents
          const view = new WebContentsView({ webContents: wc })
          view.setBackgroundColor('#00000000')
          view.setBounds({ x: 0, y: 0, width: 1, height: 1 })
          mainWindow!.contentView.addChildView(view)
          portalViews.set(portalId, view)
          wc.once('destroyed', () => {
            try {
              mainWindow?.contentView.removeChildView(view)
            } catch {}
            portalViews.delete(portalId)
          })
          return wc
        }
      }
    }

    // todo: good impl
    if (details.url) shell.openExternal(details.url)
    return { action: 'deny' }
  })

  ipcMain.on(
    'portal:update-bounds',
    (
      _e,
      payload: { id: string; bounds: { x: number; y: number; width: number; height: number } }
    ) => {
      const view = portalViews.get(payload.id)
      if (!view) return
      view.setBounds(payload.bounds)
      try {
        mainWindow!.contentView.addChildView(view)
      } catch {}
    }
  )