---
title: MARKLESS_STATE_WRITE_IN_TEMPLATE
description: "An expression in the markup writes to state."
sidebar: { hidden: true }
search: { keywords: ["STATE_WRITE_IN_TEMPLATE","state write in template","markless error"] }
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---

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

## What happened

Expressions in markup only read values. This one also writes to state, and the write wakes the same expression again.

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

```text
MARKLESS_STATE_WRITE_IN_TEMPLATE: Cannot write state inside a template expression
DOM updates are the only effects in the demand-driven graph; a write inside a branch test creates a self-waking cycle that cannot resume.
Render the value directly and move the mutation to an event handler or another explicit write site.
https://markless.dev/errors/MARKLESS_STATE_WRITE_IN_TEMPLATE
```

## How to fix it

Render the value directly. Move the write into an event handler.

## Where it comes from

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

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

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