Function: moveIndex()

Call Signature

moveIndex<T>(items, fromIndex, toIndex): readonly T[]

Defined in: collection/moveIndex/index.ts:66

Moves an element from one index to another (immutably).

Creates a new array with the element at fromIndex moved to toIndex, shifting other elements as needed. Useful for drag-and-drop reordering, priority adjustments, or any scenario requiring index-based repositioning.

Type Parameters

T

T

Parameters

items

readonly T[]

The array to modify

fromIndex

number

Index of element to move

toIndex

number

Destination index

Returns

readonly T[]

New array with element moved

Example

// Data-first: Move element forward
moveIndex(['a', 'b', 'c', 'd', 'e'], 1, 3)
// => ['a', 'c', 'd', 'b', 'e']

// Move element backward
moveIndex(['a', 'b', 'c', 'd', 'e'], 3, 1)
// => ['a', 'd', 'b', 'c', 'e']

// Drag-and-drop reordering
interface Task {
  id: number
  title: string
  priority: number
}

const tasks: Task[] = [
  { id: 1, title: 'Task 1', priority: 1 },
  { id: 2, title: 'Task 2', priority: 2 },
  { id: 3, title: 'Task 3', priority: 3 },
]

// Move task from position 0 to position 2
moveIndex(tasks, 0, 2)
// => [
//   { id: 2, title: 'Task 2', priority: 2 },
//   { id: 3, title: 'Task 3', priority: 3 },
//   { id: 1, title: 'Task 1', priority: 1 },
// ]

// No-op if indices are same
moveIndex([1, 2, 3], 1, 1)
// => [1, 2, 3]

// Negative indices (from end)
moveIndex(['a', 'b', 'c', 'd'], -1, 0)
// => ['d', 'a', 'b', 'c']

// Data-last (in pipe)
pipe(
  ['a', 'b', 'c', 'd', 'e'],
  moveIndex(1, 3)
)
// => ['a', 'c', 'd', 'b', 'e']

See

• insertAt - for adding new elements
• removeAtIndex - for removing elements
• updateAt - for replacing elements

Call Signature

moveIndex(fromIndex, toIndex): <T>(items) => readonly T[]

Defined in: collection/moveIndex/index.ts:71

Moves an element from one index to another (immutably).

Creates a new array with the element at fromIndex moved to toIndex, shifting other elements as needed. Useful for drag-and-drop reordering, priority adjustments, or any scenario requiring index-based repositioning.

Parameters

fromIndex

number

Index of element to move

toIndex

number

Destination index

Returns

New array with element moved

<T>(items): readonly T[]

Type Parameters

T

T

Parameters

items

readonly T[]

Returns

readonly T[]

Example

// Data-first: Move element forward
moveIndex(['a', 'b', 'c', 'd', 'e'], 1, 3)
// => ['a', 'c', 'd', 'b', 'e']

// Move element backward
moveIndex(['a', 'b', 'c', 'd', 'e'], 3, 1)
// => ['a', 'd', 'b', 'c', 'e']

// Drag-and-drop reordering
interface Task {
  id: number
  title: string
  priority: number
}

const tasks: Task[] = [
  { id: 1, title: 'Task 1', priority: 1 },
  { id: 2, title: 'Task 2', priority: 2 },
  { id: 3, title: 'Task 3', priority: 3 },
]

// Move task from position 0 to position 2
moveIndex(tasks, 0, 2)
// => [
//   { id: 2, title: 'Task 2', priority: 2 },
//   { id: 3, title: 'Task 3', priority: 3 },
//   { id: 1, title: 'Task 1', priority: 1 },
// ]

// No-op if indices are same
moveIndex([1, 2, 3], 1, 1)
// => [1, 2, 3]

// Negative indices (from end)
moveIndex(['a', 'b', 'c', 'd'], -1, 0)
// => ['d', 'a', 'b', 'c']

// Data-last (in pipe)
pipe(
  ['a', 'b', 'c', 'd', 'e'],
  moveIndex(1, 3)
)
// => ['a', 'c', 'd', 'b', 'e']

See

• insertAt - for adding new elements
• removeAtIndex - for removing elements
• updateAt - for replacing elements