schlange 🐍

A lightweight and flexible queue management library written in TypeScript. It provides a simple way to create and manage queues, with built-in error recovery and support for custom recovery strategies. Event-driven with event subscriptions.

Installation

Yarn

yarn add schlange

NPM

npm install schlange --save

Example

// Define a processing function for the queue
async function processData(item) {
  console.log(`Processing: ${item.data}`)
  // Simulate processing time
  await new Promise((resolve) => setTimeout(resolve, 1000))
}

// Configure the queue
const queueProps: QueueProps<string> = {
  processFunction: processData,
  idGenerator: () =>
    Math.random()
      .toString(36)
      .substr(2, 9),
}

// Create the queue
const queue = createQueue(queueProps)

// Subscribe to events
queue.onItemAdded((item) => console.log(`Item added: ${item.data}`))
queue.onItemCompleted((id) => console.log(`Item completed: ${id}`))
queue.onProcessingCompleted(() => console.log(`All done!`))

// Add items to the queue
queue.addItem('Item 1')
queue.addItem('Item 2')

API

createQueue(props: QueueProps): Queue

The createQueue function takes a QueueProps object and returns a new Queue instance.

QueueProps properties:

• processFunction: A function that will process the queue items. It should return a Promise.
• idGenerator: A function that generates unique IDs for queue items.
• recoveryStrategy (optional): A custom recovery strategy. By default, the library uses the defaultRecoveryStrategy.

Queue

The Queue instance provides the following methods and properties:

• items: An array of QueueItem<T> objects.
• isProcessing: A boolean that indicates if the queue is currently being processed.

Event subscription methods:

• onItemAdded(callback: (item: QueueItem<T>) => void)
• onItemRemoved(callback: (id: string) => void)
• onItemsChange: (callback: (items: QueueItem<T>[]) => void) => void
• onItemsCleared(callback: () => void)
• onItemUpdated(callback: (args: { id: string; updatedItem: Partial<QueueItem<T>> }) => void)
• onProcessingChange(callback: () => void)
• onItemCompleted(callback: (id: string) => void)
• onItemError(callback: (args: { id: string; error: Error }) => void)
• onProcessingCompleted(callback: () => void)

Queue manipulation methods:

• addItem(data: T): Add an item to the queue.
• removeItem(id: string): Remove an item from the queue by its ID.
• updateItem(id: string, updatedItem: Partial<QueueItem<T>>): Update an item in the queue.
• startProcessing(): Start processing the queue.
• stopProcessing(): Stop processing the queue.
• clearItems(): Clear the entire queue.
• dispose(): Dispose the queue instance and clean up resources.

Notice

This library is open source software released under the MIT license. See the LICENSE file for more information. This code is provided as-is, without any warranty or guarantee of any kind. Use at your own risk. I cannot be held responsible for any issues or damages that may arise from the use of this code. However, I have done my best to ensure that it is well-written and thoroughly tested, and I am always open to feedback and suggestions for improvement. Thank you for your understanding. I hope you enjoy using it and find it useful in your projects. If you have any questions or feedback, please don't hesitate to reach out.