Class Deque<T>

A double-ended queue with amortized O(1) insertion and removal at both ends.

Uses a sparse index map so head and tail grow independently without array shifts.

Example

const deque = new Deque<number>();
deque.push(1, 2);
deque.unshift(0);
deque.pop(); // 2

Type Parameters

T
Item type.

Index

Constructors

constructor

new Deque<T>(): Deque<T>
Type Parameters
- T
  Item type.
Returns Deque<T>

Accessors

length

get length(): number
Number of items in the deque.

Returns number
- Defined in src/data-structure/deque.ts:22

Methods

at

at(index: number): T | null
Retrieves the item at the given index.

Supports negative indices (-1 = tail). Non-integers are truncated toward zero.
Parameters
- index: number
  Position in the deque.
Returns T | null
The item, or null if out of range.
- Defined in src/data-structure/deque.ts:105

pop

pop(): T | null
Removes and returns the tail item.

Returns T | null
The removed item, or null if empty.

Remarks
Returns null (not undefined) when empty, diverging from native Array.pop().
- Defined in src/data-structure/deque.ts:63

push

push(...items: T[]): number
Appends items to the tail.
Parameters
- ...items: T[]
  Items to append (in order).
Returns number
The new length.
- Defined in src/data-structure/deque.ts:32

shift

shift(): T | null
Removes and returns the head item.

Returns T | null
The removed item, or null if empty.

Remarks
Returns null (not undefined) when empty, diverging from native Array.shift().
- Defined in src/data-structure/deque.ts:84

unshift

unshift(...items: T[]): number
Inserts items at the head.
Parameters
- ...items: T[]
  Items to insert; first argument becomes the new head.
Returns number
The new length.
- Defined in src/data-structure/deque.ts:47

Class Deque<T>

Example

Type Parameters

Index

Constructors

Accessors

Methods

Constructors

constructor

Type Parameters

Returns Deque<T>

Accessors

length

Returns number

Methods

at

Parameters

Returns T | null

pop

Returns T | null

Remarks

push

Parameters

Returns number

shift

Returns T | null

Remarks

unshift

Parameters

Returns number

Settings

On This Page