qlist

library0.14.0jsnpmunverified

qlist is a high-performance double-ended queue (deque), stack, and circular buffer implementation for Node.js. v0.14.0 provides fast O(1) operations for push/pop/shift/unshift and efficient circular buffer operations. It is designed for Node.js environments (any engine), focuses on raw speed and minimal memory overhead, and is authored by Andras. Less feature-rich than alternatives like `double-ended-queue` but optimized for speed in Node.js.

storage

npm install qlist

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · QLIST

qlist

storagejavascriptv0.14.0

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.

List

✓ import { List } from 'qlist'

✗ const qlist = require('qlist')

Requires ES module syntax. Named export only.

circularBuffer

✓ import { circularBuffer } from 'qlist'

✗ import circularBuffer from 'qlist'

The circularBuffer function is a named export, not default.

List (default)

✓ const { List } = require('qlist')

✗ const List = require('qlist')

CommonJS works with named destructuring. Do not assign the whole module to List.

Shows basic deque operations (push, shift, pop, unshift) and circular buffer usage with fixed size and overwrite behavior.

import { List } from 'qlist'; const list = new List(); list.push('a'); list.push('b'); list.unshift('first'); console.log(list.shift()); // 'first' console.log(list.pop()); // 'b' console.log(list.toArray()); // ['a'] // circular buffer usage import { circularBuffer } from 'qlist'; const cb = circularBuffer(3); cb.push(1); cb.push(2); cb.push(3); cb.push(4); // overwrites oldest (1) console.log(cb.toArray()); // [2, 3, 4] console.log(cb.get(0)); // 2

Debug

Known issues

gotchaThe library does not export a default export. Attempting to import the whole module as default will result in undefined or an error.

fix

Use named import: import { List } from 'qlist'

affects: >=0.0.0

gotchacircularBuffer returns an object with limited methods. It is not a full List instance.

fix

Only use methods documented for circularBuffer (push, get, toArray). Do not call shift/pop.

affects: >=0.0.0

gotchaThe library is intended for Node.js and may not work in browsers without bundling.

fix

Use a bundler like webpack or esbuild, or avoid code that relies on Node.js specifics.

affects: >=0.0.0

Errors

Common errors & fixes

SyntaxError: Unexpected token 'export'

Using ES module import syntax in a CommonJS module.

fix

Use require: const { List } = require('qlist'); or add 'type': 'module' to package.json.

TypeError: qlist is not a constructor

Assigning the whole module to List instead of destructuring.

fix

Use const { List } = require('qlist'); not const List = require('qlist');

Uncaught TypeError: list.shift is not a function

Using shift() on a circular buffer object that doesn't have that method.

fix

circularBuffer does not support shift/pop; use get() and manual index tracking.

Upgrade

Version history

0.14.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

20 hits · last 30 days

node

Resources

githubgit://github.com/andrasq/node-qlist ↗

packageqlist ↗

homepagehttps://github.com/andrasq/node-qlist#readme ↗