---
title: "compositionLocalOf"
description: "Create a [CompositionLocal] key that can be provided using [CompositionLocalProvider]. Changing
the value provided during recomposition will invalidate the content of [CompositionLocalProvider]
that read the value using [CompositionLocal.current].

[compositionLocalOf] creates a [ProvidableCompositionLocal] which can be used in a a call to
[CompositionLocalProvider]. Similar to [MutableList] vs. [List], if the key is made public as
[CompositionLocal] instead of [ProvidableCompositionLocal], it can be read using
[CompositionLocal.current] but not re-provided."
type: "function"
---

<div class='type'>Function</div>


<a id='references'></a>
<div class='sourceset sourceset-common'>Common</div>


```kotlin
public fun <T> compositionLocalOf(
    policy: SnapshotMutationPolicy<T> = structuralEqualityPolicy(),
    defaultFactory: () -> T,
): ProvidableCompositionLocal<T>
```


Create a `CompositionLocal` key that can be provided using `CompositionLocalProvider`. Changing
the value provided during recomposition will invalidate the content of `CompositionLocalProvider`
that read the value using `CompositionLocal.current`.

`compositionLocalOf` creates a `ProvidableCompositionLocal` which can be used in a a call to
`CompositionLocalProvider`. Similar to `MutableList` vs. `List`, if the key is made public as
`CompositionLocal` instead of `ProvidableCompositionLocal`, it can be read using
`CompositionLocal.current` but not re-provided.

#### Parameters

| | |
| --- | --- |
| policy | a policy to determine when a `CompositionLocal` is considered changed. See `SnapshotMutationPolicy` for details. |
| defaultFactory | a value factory to supply a value when a value is not provided. This factory is called when no value is provided through a `CompositionLocalProvider` of the caller of the component using `CompositionLocal.current`. If no reasonable default can be provided then consider throwing an exception. |