TypeError: Cannot convert undefined or null to object

There is a problem when mini-media-player has as source virtual entity like “media_player.spotify” from https://github.com/hassio-addons/addon-spotify-connect, other media_player sources work fine

error from the dev console on chrome:

app.a259a502.js:2 Uncaught TypeError: Cannot convert undefined or null to object
    at Function.keys (<anonymous>)
    at HTMLElement._listenKeyEventListeners (app.a259a502.js:2)
    at HTMLElement.attached (app.a259a502.js:2)
    at HTMLElement.attached (app.a259a502.js:651)
    at HTMLElement.connectedCallback (app.a259a502.js:2)
    at Va._insert (mini-media-player-bundle.js?v=1.1.3:1)
    at Va._commitNode (mini-media-player-bundle.js?v=1.1.3:1)
    at Va._commitTemplateResult (mini-media-player-bundle.js?v=1.1.3:1)
    at Va.commit (mini-media-player-bundle.js?v=1.1.3:1)
    at db (mini-media-player-bundle.js?v=1.1.3:1)

[kalkih]

Thanks @nudded, switching to ha-slider seems to indeed prevent these errors. the ha-slider component was introduced sometime in december last year so changing to it would make the card incompatible with HA versions prior to ~ 0.85.0, but we could add a check and define it if it doesn’t exist.

[nudded]

@kalkih I did some investigation and it’s related to the ha-paper-slider. It seems like the registered callback is not called, which causes _keyBindings to be empty. In other places ha-slider is used, which does not have this problem.

There is also this https://github.com/home-assistant/home-assistant-polymer/blob/dev/hassio/src/hassio-main.ts#L33 interesting comment, which seems like an ugly work-around for the same problem.