[F7 CLI] Problem when I want to use Panel Auto Initialization

Hello eveyone!
I’m learning build a mobile application with Apache Cordova and Framework7 CLI.

When I want to use Panel Auto Initialization, I add panel-init to the params of

tags, and app like this:

And when I add script this:
 <script>var panel = app.panel.get('.panel-left')

Nothing happen, and this is log in my chrome console:

log.js:24 [HMR] Waiting for update signal from WDS...
DevTools failed to load SourceMap: Could not load content for webpack:///node_modules/sockjs-client/dist/sockjs.js.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
VM15678:1 Uncaught TypeError: Cannot read property 'get' of undefined
    at <anonymous>:1:23
    at Object.insertBefore (htmldomapi.js:24)
    at patch (snabbdom.js:349)
    at eval (component-class.js:180)
(anonymous) @ VM15678:1
insertBefore @ htmldomapi.js:24
patch @ snabbdom.js:349
eval @ component-class.js:180
Promise.then (async)
eval @ component-class.js:161
Component @ component-class.js:160
create @ component.js:49
compile @ component-loader.js:46
componentLoader @ component-loader.js:87
initAppComponent @ app-class.js:234
init @ app-class.js:302
Framework7 @ app-class.js:166
eval @ app.js:26
./src/js/app.js @ app.js:4780
__webpack_require__ @ app.js:790
fn @ app.js:101
eval @ client:3
0 @ app.js:4899
__webpack_require__ @ app.js:790
(anonymous) @ app.js:857
(anonymous) @ app.js:860
client:48 [WDS] Hot Module Replacement enabled.
client:52 [WDS] Live Reloading enabled.

This is my code in app.f7.html:

So now I want to keep the left panel is open when I open this app, what I can do for this case?
Thanks you for reading. My English is so bad, so sorry.