33 lines
1.8 KiB
Markdown
33 lines
1.8 KiB
Markdown
# map-limit [](https://flattr.com/submit/auto?user_id=hughskennedy&url=http://github.com/hughsk/map-limit&title=map-limit&description=hughsk/map-limit%20on%20GitHub&language=en_GB&tags=flattr,github,javascript&category=software)[](http://github.com/hughsk/stability-badges) #
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[async.mapLimit](https://github.com/caolan/async#maplimitarr-limit-iterator-callback)'s
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functionality available as a standalone npm module.
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I often find myself pulling in [async](http://github.com/caolan/async) for this
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method alone, so in the spirit of breaking things into smaller pieces here's
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that method as a single thing you can require.
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## Usage ##
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[](https://nodei.co/npm/map-limit)
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### `mapLimit(arr, limit, iterator, callback)` ###
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The same as map only no more than "limit" iterators will be simultaneously
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running at any time.
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Note that the items are not processed in batches, so there is no guarantee
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that the first "limit" iterator functions will complete before any others are
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started.
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#### Arguments ####
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* **arr** - An array to iterate over.
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* **limit** - The maximum number of iterators to run at any time.
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* **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.
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* **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.
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## License ##
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MIT. See [LICENSE.md](http://github.com/hughsk/map-limit/blob/master/LICENSE.md) for details.
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