const itemsInInventory = [
  { name: "potato", type: "vegetables", quantity: 5 },
  { name: "banana", type: "fruit", quantity: 0 },
  { name: "chicken", type: "meat", quantity: 23 },
  { name: "apple", type: "fruit", quantity: 5 },
  { name: "beef", type: "meat", quantity: 22 },
];

// group items by type
const groupedItems = itemsInInventory.reduce((acc, item) => {
    if (!acc[item.type]) {
        acc[item.type] = [];
    }

    acc[item.type].push(item);

    return acc;
}, {});

// group items in other way
const groupedItems2 = itemsInInventory.reduce((acc, item) => {
    return {
        ...acc,
        [item.type]: [
            ...(acc[item.type] ?? []),
            item
        ],
    };
}, {});

{
    vegetable: [
        { name: 'potato', type: 'vegetable', quantity: 5 }
    ],
    fruit: [
        { name: 'banana', type: 'fruit', quantity: 0 },
        { name: 'apple', type: 'fruit', quantity: 5 },
    ],
    meat: [
        { name: 'chicken', type: 'meat', quantity: 23 },
        { name: 'beef', type: 'meat', quantity: 22 },
    ],
}

const itemsInInventory = [
  { name: "potato", type: "vegetables", quantity: 5 },
  { name: "banana", type: "fruit", quantity: 0 },
  { name: "chicken", type: "meat", quantity: 23 },
  { name: "apple", type: "fruit", quantity: 5 },
  { name: "beef", type: "meat", quantity: 22 },
];

// group items by type
const groupedItems = itemsInInventory.group(item => item.type)

console.log(JSON.stringify(groupedItems,undefined, 4))

function groupArray(items, callback) {
    return items.reduce((acc, item) => {
        const key = callback(item);
        if (!acc[key]) {
            acc[key] = [];
        }
        acc[key].push(item);
        return acc;
    }, {});
}

const groupedItems = groupArray(itemsInInventory, item => item.type);

const itemsInInventory = [
    { name: "potato", type: "vegetables", quantity: 5 },
    { name: "banana", type: "fruit", quantity: 0 },
    { name: "chicken", type: "meat", quantity: 23 },
    { name: "apple", type: "fruit", quantity: 5 },
    { name: "beef", type: "meat", quantity: 22 },
];

// group items by type
const mapOfItems = itemsInInventory.groupToMap(item => item.type)


// Result
Map {
    "vegetables" => [
        {name: "potato", type: "vegetables", quantity: 5}
    ], 
    "fruit" => [
        {name: "banana", type: "fruit", quantity: 0}, 
        {name: "apple", type: "fruit", quantity: 5}
    ],
    "meat" => [
        {name: "chicken", type: "meat", quantity: 23},
        {name: "beef", type: "meat", quantity: 22}
]} (3)

const itemsInInventory = [
    { name: "potato", type: "vegetables", quantity: 5 },
    { name: "banana", type: "fruit", quantity: 0 },
    { name: "chicken", type: "meat", quantity: 23 },
    { name: "apple", type: "fruit", quantity: 5 },
    { name: "beef", type: "meat", quantity: 22 },
];

const restock = { restock: true };
const sufficient = { restock: false };

// group items by quantity
const mapOfItems = itemsInInventory.groupToMap(
  item => item.quantity < 6 ? restock : sufficient
)


console.log(mapOfItems.get(sufficient));

// Result
[
  {name: "chicken", type: "meat", quantity: 23},
  {name: "beef", type: "meat", quantity: 22}
]