---
title: MARKLESS_STATE_CONST_REASSIGNMENT
description: "Code assigns a new value to state that was declared with const."
sidebar: { hidden: true }
search: { keywords: ["STATE_CONST_REASSIGNMENT","state const reassignment","markless error"] }
pagination: false
---

**Error** from the compiler, while it builds your `.tsrx` files.

## What happened

Markless keeps the normal JavaScript rules. A `const` binding can never get a new value, and `state()` does not change that.

Markless prints the message, the reason, and a suggestion:

```text
MARKLESS_STATE_CONST_REASSIGNMENT: Cannot update "<target>" because it was declared with const. JavaScript const binding semantics are preserved for state().
state() removes marker syntax, but it does not change JavaScript binding rules. A const binding cannot be reassigned during resume or initial render.
Use let for scalar state you reassign, or mutate a property path on object state such as menu.open.
https://markless.dev/errors/MARKLESS_STATE_CONST_REASSIGNMENT
```

Words in angle brackets change from case to case.

## How to fix it

Use `let` for state that you replace. A `const` object state still lets you change its properties, like `menu.open = true`.

```tsrx
let count = state(0);
const menu = state({ open: false });
```

## Where it comes from

`@markless/compiler` raises this code. Source:

- [packages/compiler/src/passes/state-lowering.ts](https://github.com/compiled-run/markless/blob/main/packages/compiler/src/passes/state-lowering.ts)

Read [how to read a Markless error](/tooling/diagnostics), or go back to [all error codes](/errors).