var res = JSON.parse(xhr.responseText);{
"kind": "youtube#videoListResponse",
"etag": "\"8jEFfXBrqiSrcF6Ee7MQuz8XuAM/OsgwHWh3OzIi4BGRPS9UUwdcbTc\"",
"pageInfo": {
"totalResults": 1,
"resultsPerPage": 1
},
"items": [
{
"kind": "youtube#video",
"etag": "\"8jEFfXBrqiSrcF6Ee7MQuz8XuAM/d216KOLou2jSZmJgSFMoCAX-uag\"",
"id": "MB80ZuIJATI",
"snippet": {
"publishedAt": "2017-10-25T12:03:54.000Z",
"channelId": "UCUTOwFZ5grVnUMvvleA_JMg",
"title": "Breathtaking Colors of Nature in 4K II Beautiful Flowers - Sleep Relax Music UHD TV Screensaver",
"thumbnails": {
"default": {
"url": "https://i.ytimg.com/vi/MB80ZuIJATI/default.jpg",
"width": 120,
"height": 90
},
"medium": {
"url": "https://i.ytimg.com/vi/MB80ZuIJATI/mqdefault.jpg",
"width": 320,
"height": 180
},
"high": {
"url": "https://i.ytimg.com/vi/MB80ZuIJATI/hqdefault.jpg",
"width": 480,
"height": 360
},
"standard": {
"url": "https://i.ytimg.com/vi/MB80ZuIJATI/sddefault.jpg",
"width": 640,
"height": 480
},
"maxres": {
"url": "https://i.ytimg.com/vi/MB80ZuIJATI/maxresdefault.jpg",
"width": 1280,
"height": 720
}
},
"channelTitle": "Balu - Relaxing Nature in 4K",
"categoryId": "10",
"liveBroadcastContent": "none",
"defaultLanguage": "en",
"defaultAudioLanguage": "en"
},
"contentDetails": {
"duration": "PT2H46S",
"dimension": "2d",
"definition": "hd",
"caption": "false",
"licensedContent": true,
"projection": "rectangular"
}
}
]
}
var obj = res.items[0].snippet.thumbnails;
var max_width = 0, max_height = 0, name = 'unknown';
for(let k in obj) if (max_width < obj[k].width) {
max_width = obj[k].width;
max_height = obj[k].height;
name = k;
}
console.log('Name: ',name,' Width: ',max_width,' Height: ',max_height);