Arque is a Javascript deque implementation focused on being as fast as possible. So far it is the fastest JS queue I have been able to find.

const tasks = new Arque()

tasks.isEmpty()   // true
tasks.pushBack('buy groceries')
tasks.pushBack('do taxes')
tasks.size()      // 2
tasks.peekFront() // 'buy groceries'
tasks.popFront()  // 'buy groceries'
tasks.size()      // 1
tasks.popFront()  // 'do taxes'
tasks.popFront()  // undefined

More usage examples available in test.js

Arque is implemented with an array used as a circular buffer. If you enqueue items at the same rate they are dequeued, the internal buffer will never be re-allocated.

When you enqueue more items than will fit in the internal buffer, a new buffer will be allocated that is twice as big.

An enq that happens to trigger buffer growth will individually be O(n), but since the queue capacity doubles each time this happens, the amortized performance of n enq operations is O(1).

• Currently, the internal buffer never decreases in size, to avoid unnecessary work. Auto-shrinking should maybe be the default behavior, with an option to never shrink.

• An option for a minimum buffer size (after adding shrinkage)

• An option to never grow -- need to decide how to handle the case of too many items.

• Typescript definitions

• Ability to supply initial values

• Benchmarks with alternative implementations living directly in this project and running on CI

• Make it fantasyland compatible

• Sensible method aliases

• Removing all options in favor of separate classes for each option -- should simplify code and slightly speed up execution

• Quitting javascript entirely