# List Collection (SVELTE)

A list collection is a collection that is based on an array of items. It is created by passing an array of items to the
constructor.

```ts
import { createListCollection } from '@ark-ui/react/collection'

const collection = createListCollection({
  items: [
    { label: 'Apple', value: 'apple' },
    { label: 'Banana', value: 'banana' },
  ],
})

console.log(collection.items) // [{ label: 'Apple', value: 'apple' }, { label: 'Banana', value: 'banana' }]
```

### Converting value to item

Use the `find` or `findMany` method to convert a value to an item.

```ts
const item = collection.find('banana')

console.log(item) // { label: "Banana", value: "banana" }

const items = collection.findMany(['apple', 'banana'])

console.log(items) // [{ label: "Apple", value: "apple" }, { label: "Banana", value: "banana" }]
```

### Value Traversal

Use the `getNextValue` or `getPreviousValue` method to get the next or previous item based on a value.

```ts
const nextValue = collection.getNextValue('apple')

console.log(nextValue) // banana

const previousItem = collection.getPreviousValue('banana')

console.log(previousItem) // apple
```

Likewise, use the `firstValue` or `lastValue` computed properties to get the first or last item.

```ts
console.log(collection.firstValue) // apple

console.log(collection.lastValue) // banana
```

### Check for value existence

Use the `has` method to check if a value exists in the collection.

```ts
const hasValue = collection.has('apple')

console.log(hasValue) // true
```

### Working with custom objects

If you are working with custom objects, you can pass a function to the `itemToString` and `itemToValue` options to
specify how to convert an item to a string and a value, respectively.

> By default, we look for the `label` and `value` properties in the item.

```ts
import { createListCollection } from '@ark-ui/react/collection'

const collection = createListCollection({
  items: [
    { id: 1, name: 'apple' },
    { id: 2, name: 'banana' },
    { id: 3, name: 'cherry' },
  ],
  itemToString: (item) => item.name,
  itemToValue: (item) => item.id,
})
```

To mark an item as disabled, pass a function to the `isItemDisabled` option.

> By default, we look for the `disabled` property in the item.

```ts
import { createListCollection } from '@ark-ui/react/collection'

const collection = createListCollection({
  items: [
    { id: 1, name: 'apple' },
    { id: 2, name: 'banana' },
    { id: 3, name: 'cherry' },
  ],
  isItemDisabled: (item) => item.id === 2,
})
```

### Reorder items

Use the `reorder` method to reorder items by passing the starting index and the ending index of the item to be moved.

```ts
const fromIndex = 1 // Banana
const toIndex = 0 // Apple
collection.reorder(fromIndex, toIndex)

console.log(collection.items) // [{ label: "Banana", value: "banana" }, { label: "Apple", value: "apple" }]
```