JSFiddle - React, Tailwind, and code Playground

JavaScript

var arr1 =
[
{'hour':1,'car':[{'audi':1377},{'bmw':716},{'ford':3819},{'mazda':67},{'toyota':11580},{'tesla':0}]},
{'hour':2,'car':[{'audi':1340},{'bmw':709},{'ford':3420},{'mazda':28},{'toyota':11583},{'tesla':0}]},
];

var arr = [];
for (var i = 0; i< arr1[0].car.length; i++){
	var car = arr1[0].car[i];
  var key = Object.keys(car)[0];
  arr.push({
  	car: key,
    miles: car[key]
  });
}