map-limit

map-limit

async.mapLimit's functionality available as a standalone npm module.

I often find myself pulling in async for this method alone, so in the spirit of breaking things into smaller pieces here's that method as a single thing you can require.

Usage

mapLimit(arr, limit, iterator, callback)

The same as map only no more than "limit" iterators will be simultaneously running at any time.

Note that the items are not processed in batches, so there is no guarantee that the first "limit" iterator functions will complete before any others are started.

Arguments

• arr - An array to iterate over.
• limit - The maximum number of iterators to run at any time.
• iterator(item, callback) - A function to apply to each item in the array. The iterator is passed a callback(err, transformed) which must be called once it has completed with an error (which can be null) and a transformed item.
• callback(err, results) - A callback which is called after all the iterator functions have finished, or an error has occurred. Results is an array of the transformed items from the original array.

License

MIT. See LICENSE.md for details.

Similar packages

Other packages similar to map-limit

async

The async package provides a wide range of asynchronous utilities, including the mapLimit function, which offers similar functionality to map-limit. It is more feature-rich and widely used, making it a good alternative if you need more than just map limiting.

p-limit

The p-limit package allows you to run multiple promise-returning & async functions with a concurrency limit. It is more modern and uses promises, making it a good choice for projects that prefer promise-based APIs over callback-based ones.

bluebird

Bluebird is a fully-featured promise library with a focus on performance and innovative features. It includes a map function with concurrency control, similar to map-limit, but also offers a wide range of other utilities for working with promises.