My problem is pretty straight forward I think, I just can't seem to figure it out. I need to go from an array of objects:

```
    let testArrays = [
{ "containerType": "2 Gallon", "wasteType": "10000001", "vol": "2 Gallons" },
{ "containerType": "2 Gallon", "wasteType": "10000001", "vol": "2 Gallons" },
{ "containerType": "2 Gallon", "wasteType": "10000002", "vol": "2 Gallons" },
{ "containerType": "2 Gallon", "wasteType": "10000002", "vol": "2 Gallons" },
{ "containerType": "2 Gallon", "wasteType": "10000003", "vol": "2 Gallons" },
{ "containerType": "5 Gallon", "wasteType": "10000003", "vol": "5 Gallons" },
{ "containerType": "5 Gallon", "wasteType": "10000003", "vol": "5 Gallons" },
{ "containerType": "5 Gallon", "wasteType": "10000003", "vol": "5 Gallons" },
{ "containerType": "5 Gallon", "wasteType": "10000004", "vol": "5 Gallons" }
]   

```

To a grouped object with arrays inside, grouped by "wasteType" above with counts. The volume would be created by multiplying the count by the value in "vol", which I can get with parsefloat I believe :

```
    let wastes = {
        "10000001": [
            {
                "containerType": "2 Gallon",
                "count": 2,
                "vol": "4 Gallons"
            }
        ],
        "10000002": [
            {
                "containerType": "2 Gallon",
                "count": 2,
                "vol": "4 Gallons"
            }
        ],
        "10000003": [
            {
                "containerType": "1 Gallon",
                "count": 1,
                "vol": "2 Gallons"
            },
            {
                "containerType": "5 Gallon",
                "count": 3,
                "vol": "15 Gallons"
            }
        ],
        "10000004": [
            {
                "containerType": "5 Gallon",
                "count": 1,
                "vol": "5 Gallons"
            }
        ],
    }

```

I know I should use array.map() for this but I am not sure how to do it. I have looked for this specific example everywhere and can't find it. All help is greatly appreciated.