Javascript Array containing multiple arrays which contain multiple objects

Question

I am using JSON data from Edmunds car API. Here is a simplified version of the returned data:

[[
 {drivenWheels: "front wheel drive", price: 32442},
 {drivenWheels: "front wheel drive", price: 42492},
 {drivenWheels: "front wheel drive", price: 38652},
 {drivenWheels: "front wheel drive", price: 52402}
 ],
 [{drivenWheels: "all wheel drive", price: 29902},
  {drivenWheels: "all wheel drive", price: 34566},
  {drivenWheels: "all wheel drive", price: 33451},
  {drivenWheels: "all wheel drive", price: 50876}
 ]
]

In this example there are 2 inner arrays that represent the different options of drive train available for this car model (front and all wheel).

I am trying to find the lowest price for each respective drive train and push the object into a new array. In my example I would like the final result to be..

var finalArr = [{drivenWheels: "front wheel drive", price: 32442},{drivenWheels: "all wheel drive", price: 29902}]

I have been trying to solve this for a while now and can't figure it out. Here is what I have so far.

function findLowestPriceDrivenWheels(arr){
    var wheelAndPriceArr = [];
    var shortest = Number.MAX_VALUE;
    for (var i = 0; i < arr.length; i++){
        //loops inner array
        for (var j = 0; j < arr[i].length; j++){
            if(arr[i][j].price < shortest){
                shortest = arr[i][j].price;
                wheelAndPriceArr.length = 0;
                wheelAndPriceArr.push(arr[i][j]);
            }
        }  
    }
    console.log(wheelAndPriceArr);
    return wheelAndPriceArr;
}

If there is 1 inner array. I can get it to work. The problem is when there are 2,3 or 4 inner arrays (representing drive trains). I would like to write a function that can handle any number of drive trains that the API returns. I actually understand why my solution doesn't work. The problem is that I'm new and I've hit a brick wall of understanding. The solution is slightly out of my grasp.

Here are 2 similiar questions that were helpful but they deal with 1 inner array and I still can't figure it out. Any help would be appreciated! Here and Here

Answer 1

Assumes arr is your JSON

var results = [];
arr.forEach(function(a,i){a.forEach(function(b){(!results[i]||b['price'] < results[i]['price'])&&(results[i]=b);});});

I'm a huge fan of one-liners

Result (Copy pasted from console)

[
    {
        "drivenWheels":"front wheel drive",
        "price":32442
    },
    {
        "drivenWheels":"all wheel drive",
        "price":29902
    }
]

---

More strait-forward

var results = [],
    i;

for (i = 0; i < arr.length; i += 1) {
    var a = arr[i],
        j;

    for (j = 0; j < a.length; j += 1) {
        var b = a[j];
        //  !results[i] will check if there is a car for the current drivenWheels. It will return true if there isn't
        if (!results[i] || b['price'] < results[i]['price']) {
            results[i] = b;
        }
    }
}