svelte/documentation/docs/98-reference/30-runtime-errors.md

---
title: 'Runtime Errors'
generated: 'generated by process-messages/index.js'
---

## bind_invalid_checkbox_value

```
Using `bind:value` together with a checkbox input is not allowed. Use `bind:checked` instead
```

## bind_invalid_export

```
Component %component% has an export named `%key%` that a consumer component is trying to access using `bind:%key%`, which is disallowed. Instead, use `bind:this` (e.g. `<%name% bind:this={component} />`) and then access the property on the bound component instance (e.g. `component.%key%`)
```

## bind_not_bindable

```
A component is attempting to bind to a non-bindable property `%key%` belonging to %component% (i.e. `<%name% bind:%key%={...}>`). To mark a property as bindable: `let { %key% = $bindable() } = $props()`
```

## component_api_changed

```
%parent% called `%method%` on an instance of %component%, which is no longer valid in Svelte 5. See https://svelte-5-preview.vercel.app/docs/breaking-changes#components-are-no-longer-classes for more information
```

## component_api_invalid_new

```
Attempted to instantiate %component% with `new %name%`, which is no longer valid in Svelte 5. If this component is not under your control, set the `compatibility.componentApi` compiler option to `4` to keep it working. See https://svelte-5-preview.vercel.app/docs/breaking-changes#components-are-no-longer-classes for more information
```

## derived_references_self

```
A derived value cannot reference itself recursively
```

## each_key_duplicate

```
Keyed each block has duplicate key at indexes %a% and %b%
```
```
Keyed each block has duplicate key `%value%` at indexes %a% and %b%
```

## effect_in_teardown

```
`%rune%` cannot be used inside an effect cleanup function
```

## effect_in_unowned_derived

```
Effect cannot be created inside a `$derived` value that was not itself created inside an effect
```

## effect_orphan

```
`%rune%` can only be used inside an effect (e.g. during component initialisation)
```

## effect_update_depth_exceeded

```
Maximum update depth exceeded. This can happen when a reactive block or effect repeatedly sets a new value. Svelte limits the number of nested updates to prevent infinite loops
```

## hydration_failed

```
Failed to hydrate the application
```

## invalid_snippet

```
Could not `{@render}` snippet due to the expression being `null` or `undefined`. Consider using optional chaining `{@render snippet?.()}`
```

## lifecycle_legacy_only

```
`%name%(...)` cannot be used in runes mode
```

## props_invalid_value

```
Cannot do `bind:%key%={undefined}` when `%key%` has a fallback value
```

## props_rest_readonly

```
Rest element properties of `$props()` such as `%property%` are readonly
```

## rune_outside_svelte

```
The `%rune%` rune is only available inside `.svelte` and `.svelte.js/ts` files
```

## state_descriptors_fixed

```
Property descriptors defined on `$state` objects must contain `value` and always be `enumerable`, `configurable` and `writable`.
```

## state_prototype_fixed

```
Cannot set prototype of `$state` object
```

## state_unsafe_local_read

```
Reading state that was created inside the same derived is forbidden. Consider using `untrack` to read locally created state
```

## state_unsafe_mutation

```
Updating state inside a derived is forbidden. If the value should not be reactive, declare it without `$state`
```

## lifecycle_function_unavailable

```
`%name%(...)` is not available on the server
```

## invalid_default_snippet

```
Cannot use `{@render children(...)}` if the parent component uses `let:` directives. Consider using a named snippet instead
```

## lifecycle_outside_component

```
`%name%(...)` can only be used during component initialisation
```

## store_invalid_shape

```
`%name%` is not a store with a `subscribe` method
```

## svelte_element_invalid_this_value

```
The `this` prop on `<svelte:element>` must be a string, if defined
```