---
title: "isZoomExpression | 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 isZoomExpression

-   isZoomExpression(  
        expression: any,  
    ): expression is  
        | [ZoomConstantExpression](https://docs.maptiler.com/sdk-js/api-reference/classes/ZoomConstantExpression/)<"source"\>  
        | [ZoomDependentExpression](https://docs.maptiler.com/sdk-js/api-reference/classes/ZoomDependentExpression/)<"source"\>[](#iszoomexpression)
    
    #### Parameters
    
    -   expression: any
    
    #### Returns expression is  
        | [ZoomConstantExpression](https://docs.maptiler.com/sdk-js/api-reference/classes/ZoomConstantExpression/)<"source"\>  
        | [ZoomDependentExpression](https://docs.maptiler.com/sdk-js/api-reference/classes/ZoomDependentExpression/)<"source"\>