Function fetchSSE

src/services/utils/sse.ts:29–76

(options: FetchSSEOptions)

 * Promise 在流结束时 resolve，出错时 reject。
 */
export async function fetchSSE(options: FetchSSEOptions): Promise<void> {
  const { url, method = 'POST', headers = {}, body, signal, onEvent } = options

  const resp = await fetchWithAuth(url, {
    method,
    headers: { 'Content-Type': 'application/json', ...headers },
    body: body != null ? JSON.stringify(body) : undefined,
    signal,
  })

  if (!resp.ok) {
    const text = await resp.text().catch(() => '')
    throw new Error(`SSE request failed: HTTP ${resp.status} ${text}`)
  }

  if (!resp.body) {
    throw new Error('SSE response has no body')
  }

  const reader = resp.body.getReader()
  const decoder = new TextDecoder()
  let buffer = ''
  let currentEvent = ''

  while (true) {
    const { done, value } = await reader.read()
    if (done) break

    buffer += decoder.decode(value, { stream: true })
    const lines = buffer.split('\n')
    buffer = lines.pop() || ''

    for (const line of lines) {
      if (line.startsWith('event: ')) {
        currentEvent = line.slice(7).trim()
      } else if (line.startsWith('data: ')) {
        onEvent({ event: currentEvent, data: line.slice(6) })
        currentEvent = ''
      }
    }
  }

  if (buffer.trim()) {
    if (buffer.startsWith('data: ')) {
      onEvent({ event: currentEvent, data: buffer.slice(6) })
    }
  }
}

/**
 * 便捷方法：发起 SSE 请求，按 event type 分发解析后的 JSON。