---
title: "isExpression | 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 isExpression

-   isExpression(expression: unknown): boolean[](#isexpression)
    
    #### Parameters
    
    -   expression: unknown
    
    #### Returns boolean