---
title: "createFunction | JavaScript maps SDK"
description: "Documentation for MapTiler SDK"
---

> For AI agents: a documentation index is available at [/llms.txt](https://docs.maptiler.com/llms.txt). Markdown versions of all pages are available by appending .md to any URL.

# Function createFunction

-   createFunction(  
        parameters: any,  
        propertySpec: any,  
    ):  
        | {  
            interpolationFactor: any;  
            interpolationType: { name: string };  
            kind: string;  
            zoomStops: any\[\];  
            evaluate(\_\_namedParameters: { zoom: any }, properties: any): any;  
        }  
        | {  
            evaluate: (\_\_namedParameters: { zoom: any }) \=> any;  
            interpolationFactor: any;  
            interpolationType: { base: any; name: string };  
            kind: string;  
            zoomStops: any;  
        }  
        | {  
            interpolationFactor?: undefined;  
            interpolationType?: undefined;  
            kind: string;  
            zoomStops?: undefined;  
            evaluate(\_: any, feature: any): any;  
        }[](#createfunction)
    
    #### Parameters
    
    -   parameters: any
    -   propertySpec: any
    
    #### Returns  
        | {  
            interpolationFactor: any;  
            interpolationType: { name: string };  
            kind: string;  
            zoomStops: any\[\];  
            evaluate(\_\_namedParameters: { zoom: any }, properties: any): any;  
        }  
        | {  
            evaluate: (\_\_namedParameters: { zoom: any }) \=> any;  
            interpolationFactor: any;  
            interpolationType: { base: any; name: string };  
            kind: string;  
            zoomStops: any;  
        }  
        | {  
            interpolationFactor?: undefined;  
            interpolationType?: undefined;  
            kind: string;  
            zoomStops?: undefined;  
            evaluate(\_: any, feature: any): any;  
        }