vscode-extension-samples/notebook-renderer-sample/.vscode/launch.json

// A launch configuration that compiles the extension and then opens it inside a new window
{
  "version": "0.2.0",
  "configurations": [
      {
          "name": "Launch Extension",
          "type": "extensionHost",
          "request": "launch",
          "runtimeExecutable": "${execPath}",
          "args": [
            "--extensionDevelopmentPath=${workspaceFolder}",
            "--folder-uri=${workspaceFolder}/sample/",
            "${workspaceFolder}/sample/sample.ipynb"
          ],
          "outFiles": [
              "${workspaceFolder}/out/**/*.js"
          ],
          "preLaunchTask": "npm: webpack"
      }
  ]
}