# Can't use length filter in a custom normalizer. any way around?
**URL:** https://discuss.elastic.co/t/cant-use-length-filter-in-a-custom-normalizer-any-way-around/117533
**Category:** Elasticsearch
**Created:** [January 29, 2018, 9:14pm UTC](https://discuss.elastic.co/t/cant-use-length-filter-in-a-custom-normalizer-any-way-around/117533 "2018-01-29T21:14:18Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@anon44344346](https://discuss.elastic.co/u/anon44344346)
#### Post date: [January 29, 2018, 9:14pm UTC](https://discuss.elastic.co/t/cant-use-length-filter-in-a-custom-normalizer-any-way-around/117533/1 "2018-01-29T21:14:18Z")
I know "normalizer doesn't like trim filter", but I've also found out I can't use length filter either.
Is there any way of knowing in advance which filters are accepted in a normalizer definition?
What I try to accomplish with the length filter is to avoid empty string values. I did that with the "length" filter with this:
{
"type": "length",
"min": 1
}
only tokens of at least 1 character would go through.
I'm trying to accomplish the same using a normalizer, but it doesn't like "length" filter.
any ideas??
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [February 26, 2018, 9:14pm UTC](https://discuss.elastic.co/t/cant-use-length-filter-in-a-custom-normalizer-any-way-around/117533/2 "2018-02-26T21:14:18Z")
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