d4c-queue

library1.7.1jsnpmunverified

A TypeScript task queue library (v1.7.1) that wraps async/promise-returning/sync functions into queue-ready functions. Supports sequential (FIFO) and concurrent execution with configurable concurrency limits. Includes ES6 builds (CommonJS and ES modules), optional decorators (@synchronized, @concurrent), sub-queues via tags, and features like inheriting errors from previous tasks, non-blocking execution, and dropping tasks when limit is reached. Fully typed, well-tested, works in Node.js (>=10) and browsers. Differences from other queues: O(1) FIFO performance, decorator support, and fine-grained concurrency control via instance or class methods.

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npm install d4c-queue

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INSTALL

IMPORT

SIG · D4C-QUEUE

d4c-queue

devopsjavascriptv1.7.1

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.

D4C

✓ import { D4C } from 'd4c-queue'

✗ import D4C from 'd4c-queue'

Named export, not default. Also available via CommonJS require.

synchronized

✓ import { synchronized } from 'd4c-queue'

✗ import { Sync } from 'd4c-queue'

Decorator for sequential execution. Requires experimentalDecorators in TypeScript.

concurrent

✓ import { concurrent } from 'd4c-queue'

✗ import { Concurrent } from 'd4c-queue'

Decorator for concurrent execution. Requires experimentalDecorators.

QConcurrency

✓ import { QConcurrency } from 'd4c-queue'

✗ const { QConcurrency } = require('d4c-queue')

Both ES import and CommonJS require work.

Demonstrates creating a D4C queue instance, wrapping functions, and sequential vs. concurrent execution.

import { D4C } from 'd4c-queue'; // Create a D4C instance with sequential execution (default) const queue = new D4C(); // Wrap a function const myTask = queue.wrap(async (x: number) => { return x * 2; }); // Call it multiple times; they execute sequentially Promise.all([ myTask(1), myTask(2), ]).then(results => { console.log(results); // [2, 4] }); // Concurrent mode with limit 2 const concurrentQueue = new D4C({ concurrency: 2 }); const task = concurrentQueue.wrap(async (x: number) => { return x * 3; }); Promise.all([ task(1), task(2), task(3), ]).then(results => { console.log(results); // [3, 6, 9] });

Debug

Known issues

breakingv1.0.0 changed the API from callback-based to promise-based. Old code using callbacks will break.

fix

Migrate to promise-based API: use async/await or .then().

affects: <1.0.0

gotchaDecorators (@synchronized, @concurrent) require TypeScript's experimentalDecorators: true in tsconfig.json. Without it, they will not work and may cause compile errors.

fix

Add "experimentalDecorators": true to compilerOptions in tsconfig.json.

affects: >=1.0.0

gotchaThe wrap method returns a new function; the original function is not modified. Calling the original function directly bypasses the queue.

fix

Always use the wrapped function for queued execution. Store the returned function and call it.

affects: >=1.0.0

deprecatedThe previous decorator names @Synchronized and @Concurrent (capital S/C) were deprecated in v1.5.0 and removed in v1.6.0.

fix

Use @synchronized and @concurrent (lowercase) instead.

affects: >=1.5.0 <1.6.0

Errors

Common errors & fixes

TypeError: Class constructor D4C cannot be invoked without 'new'

Using D4C as a function without 'new' keyword.

fix

Use 'new D4C()' to create an instance.

TS1254: A 'super' call must be a root-level ternary expression

Decorator syntax error when using @synchronized on a class method without correct experimentalDecorators setting.

fix

Enable 'experimentalDecorators' in tsconfig.json and ensure target >= ES5.

Error: QueueIsFull

Calling a wrapped function when dropWhenReachLimit is true and concurrency limit is reached.

fix

Catch the error and handle gracefully, or increase concurrency limit, or avoid dropping by setting dropWhenReachLimit to false.

Upgrade

Version history

1.7.1latest on npm

Audit

Dependencies

@babel/plugin-proposal-decoratorsoptionalRequired for JavaScript users who want to use decorators; not needed for TypeScript.

Agent activity

7 hits · last 30 days

node

Resources

githubhttps://github.com/grimmer0125/d4c-queue ↗

packaged4c-queue ↗

homepagehttps://grimmer0125.github.io/d4c-queue ↗