denque

library2.1.0jsnpmunverified

Denque is a high-performance double-ended queue (deque) implementation for JavaScript/Node.js, version 2.1.0. It provides O(1) operations for push, pop, shift, unshift, and random access via peekAt(index). Zero dependencies, ships TypeScript definitions. Maintained by Invertase, used by official Redis, MongoDB, MariaDB, MySQL and Redis clients. Outperforms other deque libraries like double-ended-queue in benchmarks.

storage

npm install denque

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · DENQUE

denque

storagejavascriptv2.1.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Denque

✓ import Denque from 'denque'

✗ const Denque = require('denque').default

ESM default import works directly.

Denque (CommonJS)

✓ const Denque = require('denque')

✗ const Denque = require('denque').Denque

CJS require returns the constructor directly.

Denque type

✓ import type Denque from 'denque'

✗ import { Denque } from 'denque'

TypeScript: use import type for type-only usage.

Create a Denque, push/unshift elements, shift/pop, and peek at index.

import Denque from 'denque'; const queue = new Denque([1, 2, 3]); queue.push(4); // [1,2,3,4] queue.unshift(0); // [0,1,2,3,4] console.log(queue.shift()); // 0 console.log(queue.pop()); // 4 console.log(queue.peekAt(1)); // 2 console.log(queue.length); // 3

Debug

Known issues

gotchaDenque uses a circular buffer: internal capacity may not match length. Calling .toArray() returns a copy of the logical elements.

fix

Use .toArray() or iterate with .get(i) instead of relying on internal array.

affects: all

gotchapeekAt(index) accepts negative indices for reverse indexing (like Array). But -1 returns the last element, not the first.

fix

peekAt(-1) is safe, but be careful with negative out-of-bounds (returns undefined).

affects: all

gotchaDenque does not support .slice(), .splice(), or other Array methods. It only provides deque operations.

fix

Convert to array via .toArray() and then use array methods.

affects: all

deprecatedIn v1.x, .remove(...) existed but was removed in v2. Use .splice()? No, Denque has no splice. Use manual shift/pop or toArray.

fix

Use .toArray() and re-create Denque for removal by index.

affects: >=2.0.0

Errors

Common errors & fixes

Cannot find module 'denque' or 'denque' is not a constructor

CommonJS require for default export when package is ESM-only? Denque provides CJS, but some bundlers may mangle.

fix

Use import Denque from 'denque' or const Denque = require('denque') as appropriate.

Denque.peekAt is not a function

Calling static method on instance without parentheses? Actually instance method. Possible typo: using Denque.peekAt instead of instance.peekAt.

fix

const d = new Denque(); d.peekAt(0);

Property 'push' does not exist on type 'Denque<unknown>'

TypeScript strict: type inference issue when not specifying generic.

fix

new Denque<number>([1,2,3]);

Upgrade

Version history

2.1.0latest on npm

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Dependencies

No dependency data recorded yet.

Agent activity

28 hits · last 30 days

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OpenAI (training)

Resources

githubhttps://github.com/invertase/denque ↗

packagedenque ↗

homepagehttps://docs.page/invertase/denque ↗