# upgradeWebSocket

**Kind:** Constant

**Source:** [`src/adapter/cloudflare-workers/websocket.ts`](https://github.com/honojs/hono/blob/main/src/adapter/cloudflare-workers/websocket.ts#L5)

**Part of:** [Adapter](subsystem-src-adapter)

## Definition

```ts
UpgradeWebSocket< WebSocket, any, Omit<WSEvents<WebSocket>, 'onOpen'> >
```

## Value

```ts
defineWebSocketHelper(async (c, events) => {
  const upgradeHeader = c.req.header('Upgrade')
  if (upgradeHeader !== 'websocket') {
    return
  }

  // @ts-expect-error WebSocketPair is not typed
  const webSocketPair = new WebSocketPair()
  const client: WebSocket = webSocketPair[0]
  const server: WebSocket = webSocketPair[1]

  const wsContext = new WSContext<WebSocket>({
    close: (code, rea…
```

## Relationships

- IMPORTS → `WSContext`
- IMPORTS → `defineWebSocketHelper`