Iterate through object in svelte

I am using Svelte and was wondering why this won't log anything? Is it something to do with reactivity? I am trying to iterate over an object.

let videoElement: HTMLVideoElement;$: captionLines = [''];$: console.log('captionLines', captionLines);if (videoElement && videoElement.textTracks) {    console.log(videoElement.textTracks);    if (videoElement.textTracks.length >= 0) {        //get to this point...        Object.keys(videoElement.textTracks).forEach((key) => {            //nothing logs here...            console.log(key, videoElement.textTracks[key]);    });}

Log: