---
url: /process-functions/js-support.md
description: >-
  The MODLR scripting engine includes a small set of common JavaScript utilities
  that web and Node.js developers typically expect.
---

# Supported JavaScript Features

The MODLR scripting engine includes a small set of **common JavaScript utilities** that web and Node.js developers typically expect.

These features behave similarly to their browser counterparts and are safe to use inside MODLR scripts.

## Available Features

### URL Utilities

* `URL`\
  <https://developer.mozilla.org/en-US/docs/Web/API/URL>
* `URLSearchParams`\
  <https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams>

### Base64 Helpers

* `atob`\
  <https://developer.mozilla.org/en-US/docs/Web/API/atob>
* `btoa`\
  <https://developer.mozilla.org/en-US/docs/Web/API/btoa>

### Standard JavaScript Language Features

The scripting engine supports a **modern subset of ECMAScript (ES2020+)**.

This includes most commonly used language features such as:

* `let` / `const`
* Arrow functions
* Destructuring
* Spread (`...`)
* Template strings
* Optional chaining (`?.`)
* Nullish coalescing (`??`)
* Modern array methods (`map`, `filter`, `reduce`, etc.)

If it's standard, non-async JavaScript syntax, it will generally work as expected.

## Not Supported

The scripting engine does **not** currently support:

* async/await
* Promises
* fetch()
* DOM or browser APIs
* setTimeout / setInterval