vscode-extension-samples/webview-sample/.vscode/launch.json

// A launch configuration that compiles the extension and then opens it inside a new window
{
    "version": "0.1.0",
    "configurations": [
        {
            "name": "Launch Extension",
            "type": "extensionHost",
            "request": "launch",
            "runtimeExecutable": "${execPath}",
            "args": [
                "--extensionDevelopmentPath=${workspaceRoot}"
            ],
            "stopOnEntry": false,
            "sourceMaps": true,
            "outDir": "${workspaceRoot}/out/src",
            "preLaunchTask": "npm"
        }
    ]
}