SimpleQueue v1.0.0
SimpleQueue
A simple FIFO queue
npm install SimpleQueueWhat is this?
There are plenty queues for node, but even those branded as FIFO (first in first out) usually destroy the order. Eg. when mapping over an RSS feeds & doing something with all of the pages, you need to know what element had what position - so I created this little helper.
API
Class: SimpleQueue\<T, R>
A simple FIFO queue, delivering items in order.
Type parameters
| Name | Default | Description |
|---|---|---|
T | - | Type that is pushed onto the stack. |
R | void | Type that the passed callback maps to. |
Constructors
constructor
+ new SimpleQueue(worker: (element: T, callback: (error: Error | null, result: R) => void) => void, callback: (error: Error | null, result: R, element: T) => void, done?: undefined | () => void, concurrent?: number): SimpleQueue
Defined in index.ts:16
Creates a new FIFO queue.
Parameters:
| Name | Type | Default value | Description |
|---|---|---|---|
worker | (element: T, callback: (error: Error | null, result: R) => void) => void | - | Method to call for each child. Args: |
callback | (error: Error | null, result: R, element: T) => void | - | Method to call when an element was processed. |
done? | undefined | () => void | - | Method to call once the stack is cleared. |
concurrent | number | 20 | Number of elements to process in parallel. Defaults to 20. |
Returns: SimpleQueue
Properties
paused
• paused: boolean = false
Defined in index.ts:16
Methods
abort
▸ abort(): void
Defined in index.ts:48
Clears the queue (can't stop running processes).
Returns: void
pause
▸ pause(): void
Defined in index.ts:57
Pause the queue execution. Will not stop already in-flight items.
Returns: void
push
▸ push(props: T): void
Defined in index.ts:41
Adds an element to the queue.
Parameters:
| Name | Type |
|---|---|
props | T |
Returns: void
resume
▸ resume(): void
Defined in index.ts:64
Resume the queue execution, and catch up with remaining items.
Returns: void
Example
import SimpleQueue from "SimpleQueue";
const queue = new SimpleQueue(
(element, callback) => {
// Set
setTimeout(() => callback(null, element / 1000), element);
},
(err, result, element) => {
console.log(result);
},
() => {
console.log("done");
},
4
);
queue.push(1000);
queue.push(5000);
queue.push(3000);
queue.push(4000);
queue.push(8000);
queue.push(2000);
queue.push(0);Output:
1, 5, 3, 4, 8, 2, 0, "done"This takes 9 seconds to run.