Keep creating app.js when upgrading Sencha Cmd and had renamed default app.js

In app.json I have the following and the application works fine, but I always need to delete the generated app.js after I upgrade Sencha Cmd or I upgrade of Ext JS version or the application may not start.

Code:

    "js": [
        {
            "path": "OPApp.js",
            "bundle": true
        }
    ]

Keep creating app.js when upgrading Sencha Cmd and had renamed default app.js