JSFiddle - React, Tailwind, and code Playground

HTML

<button onclick='getData()'>Get Data</button>

JavaScript

var fileId = '0B3PTzGTCiOZySkFtRG00X0hsTGc'
		var url = 'https://www.googleapis.com/drive/v2/files/' + fileId + '?alt=media';
		var oauthToken = 'Bearer ya29.dAHqVybl2it-LCUpFJBOUX7u-pbKPMxf5zsMEEVyNHsqCu9ip05bQy9lIGR2iakwlqw_ORrpw0k3eQ'			
		var options = {
			method : 'get',
			headers : {
				Authorization : oauthToken
			}
		}		
		
		var getData = function() {
			var chunked = false;
			var allData = '';
			fetch(url, options).then(function(response) {
				if(response.status === 200 || response.status === 0) {
					if(response.headers.get('content-length')){
						console.log('Non chunked data');
						chunked = false;
					} else {
						console.log('chunked data');
						chunked = true;
					}
				}				
			}).then(function(data){
				if(chunked){
					allData += data;
					console.log('Aggregating chunked data');
				} else {
					allData = data;
					console.log('Got all data at once');
				}
				console.log(allData);
			}).then().catch();
		}