---
schema_version: "1"
id: 236f6f502ec45574e82892bbae986143d8455cbd5391a70bb8bed446d23ece94
title: functionParamTypes
collection: mulesoft
version: current
locale: en-us
portal_url: https://docs.salesforce.com/mulesoft/current/en-us/dataweave/latest/dw-types-functions-functionparamtypes.md
canonical_url: https://docs.mulesoft.com/dataweave/latest/dw-types-functions-functionparamtypes
source_site: docs.mulesoft.com
content_type: documentation
content_hash: 21251c2772064b7a2b9f945793b26e6d8aecbe62f1008a5bd716e3a76027fc36
description: MuleSoft Documentation Site
release: "2.13"
latest: true
---
---
product: DataWeave
version: 2.13
is-latest-version: true
---

# functionParamTypes

> For the full documentation index, see: https://docs.mulesoft.com/llms.txt

## functionParamTypes(t: Type): Array<FunctionParam>

Returns the list of parameters from the given function type. This function fails if the provided
type is not a Function type.

_Introduced in DataWeave version 2.3.0._

### Parameters

<table><colgroup><col> <col></colgroup><thead><tr><th>Name</th><th>Description</th></tr></thead><tbody><tr><td><p><code>t</code></p></td><td><p>The function type.</p></td></tr></tbody></table>

### Example

This example shows how `functionParamTypes` behaves with different inputs.

#### Source

```DataWeave
%dw 2.0
output application/json
import * from dw::core::Types
type AFunction = (String, Number) -> Number
type AFunction2 = () -> Number
---
{
    a: functionParamTypes(AFunction),
    b: functionParamTypes(AFunction2)
}
```

#### Output

```Json
{
   "a": [
     {
       "paramType": "String",
       "optional": false
     },
     {
       "paramType": "Number",
       "optional": false
     }
   ],
   "b": [

   ]
 }
```