# MessageComposer
> **Info:** This is release candidate documentation for **Stream Chat React SDK v15**. For the latest stable version, see the [latest version (v14)](https://getstream.io/chat/docs/sdk/react/).
`MessageComposer` renders the message input of a channel or a thread. The message being written lives in a `MessageComposer` object from `stream-chat`, such as `channel.messageComposer`. The component renders that object and calls it when the user types, attaches or sends. [Message composer UI](https://getstream.io/chat/docs/sdk/react/v15/ui/components/message-composer-ui/) explains the parts it renders and which composer it writes into, and [Message composer](https://getstream.io/chat/docs/sdk/react/v15/state/writing-messages/message-composer/) explains the object.
## Best practices
- Render it inside a `Channel` or a `Thread`. It writes into that thread's or channel's composer, and throws outside both.
- Change what is sent in the state layer, not in the component: transform the message with [composer middleware](https://getstream.io/chat/docs/sdk/react/v15/state/writing-messages/composer-middleware/), or replace the request with a `sendMessageRequest` handler, as [Customizing requests](https://getstream.io/chat/docs/sdk/react/v15/state/writing-messages/message-operations/#customizing-requests) shows.
- Change the look with `WithComponents`. Scope the override around one `MessageComposer` when only that composer should differ.
- To tell a thread composer from a channel one in your own parts, read `useMessageComposerController().threadId`. It's set only for a thread's composer.
## Basic usage
```tsx
import {
Channel,
ChannelHeader,
MessageComposer,
MessageList,
Thread,
ThreadHeader,
} from "stream-chat-react";
export const ChannelPane = () => (
);
export const ThreadPane = () => (
);
```
The first composer writes into `channel.messageComposer`, the second into `thread.messageComposer`.
## UI customization
`MessageComposer` renders the component registered as `MessageComposerUI`, and provides [`MessageComposerContext`](https://getstream.io/chat/docs/sdk/react/v15/component-reference/message-composer/messagecomposercontext/) to it. The default `MessageComposerUI` is built from parts, each with an override key of its own:
- To replace one part, such as the send button or the attachment selector, register it under its key. [Message composer UI](https://getstream.io/chat/docs/sdk/react/v15/ui/components/message-composer-ui/#replacing-parts) lists the keys, and [Composer UI components](https://getstream.io/chat/docs/sdk/react/v15/component-reference/message-composer/composer-ui-components/) has their props.
- To replace the whole layout, register your own `MessageComposerUI`. See [Input UI](https://getstream.io/chat/docs/sdk/react/v15/component-reference/message-composer/input-ui/).
When unmounted, `MessageComposer` saves a draft of the composer if drafts are turned on, and then clears the thread's or channel's composer. See [Drafts](https://getstream.io/chat/docs/sdk/react/v15/features/messaging/drafts/).
## Supplying a composer
By default, `MessageComposer` writes into the composer of the thread or channel it's rendered in. Wrap it in `MessageComposerControllerProvider` to have it write into a composer you create instead, for example one that edits a message where it sits. Every `MessageComposer` and composer hook below the provider uses the supplied composer.
A supplied composer belongs to you:
- When `MessageComposer` unmounts, it saves the composer's draft if drafts are on for it, but it never clears the composer. Clear it yourself when the composition ends.
- Submitting works as for any composer: `MessageComposer.update()` while a message is being edited, `MessageComposer.send()` otherwise.
### Edit a message inline
An edit composer has the message as its composition context. This one shows a `MessageComposer` for the message while the edit is in progress:
```tsx
import { useState } from "react";
import type { LocalMessage, MessageComposerState } from "stream-chat";
import { MessageComposer as MessageComposerController } from "stream-chat";
import {
MessageComposer,
MessageComposerControllerProvider,
useChatContext,
useStateStore,
} from "stream-chat-react";
const editingSelector = (state: MessageComposerState) => ({
isEditing: state.editedMessage !== null,
});
export const InlineEditor = ({ message }: { message: LocalMessage }) => {
const { client } = useChatContext();
const [composer] = useState(
() =>
new MessageComposerController({
client,
composition: message,
compositionContext: message,
}),
);
const { isEditing } = useStateStore(composer.state, editingSelector);
if (!isEditing) return null;
return (
);
};
```
Saving the edit, or cancelling it with the ✕ on the edit preview, empties the composer, and the editor disappears. [Editing a message in place](https://getstream.io/chat/docs/sdk/react/v15/features/messaging/sending-editing-and-deleting/#editing-a-message-in-place) shows where to render it and how to open it from the Edit action.
## Props
| Prop | Type | Default | Description |
| ------------------------------- | ------------------------------------------------------------------------------------------------------------- | ------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `additionalTextareaProps` | `Omit, "defaultValue" \| "style" \| "disabled" \| "value">` | none | Props for the `