---
url: "https://vueda.dev/v3/reference/api/js/utils/fieldMappings/functions/mergeFilterFieldMapping.md"
title: "mergeFilterFieldMapping"
---

# mergeFilterFieldMapping

## Overview

Register custom filter types, or adjust existing ones, for filter forms. Each
entry's components merge into filterFieldMapping; its `initialValue`,
`array`, `range`, and `repeatedKey` keys merge into the value table
(FilterFieldMappings). A filter type needs both to be
offered in a list's filter menu: the value table tells the form what an empty
or URL-restored value looks like, and the component table tells it what to
render.

## Signature

`mergeFilterFieldMapping(customMappings)`

### Parameters

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| <span id="param-customMappings">customMappings</span> | `object` | yes | Registrations keyed by filter type. |

### Returns

`The updated filter field mappings.`

## Examples

```js
mergeFilterFieldMapping({
    MyCustomField: { component: MyCustomField, widget: MyCustomWidget, initialValue: null },
});
```

## Source

`client/lib/utils/fieldMappings.js:938`