Function nestedUnrollBuffer

packages/server-renderer/src/renderToString.ts:14–50

(
  buffer: SSRBuffer,
  parentRet: string,
  startIndex: number,
)

const { isVNode } = ssrUtils

function nestedUnrollBuffer(
  buffer: SSRBuffer,
  parentRet: string,
  startIndex: number,
): Promise<string> | string {
  if (!buffer.hasAsync) {
    return parentRet + unrollBufferSync(buffer)
  }

  let ret = parentRet
  for (let i = startIndex; i < buffer.length; i += 1) {
    const item = buffer[i]
    if (isString(item)) {
      ret += item
      continue
    }

    if (isPromise(item)) {
      return item.then(nestedItem => {
        buffer[i] = nestedItem
        return nestedUnrollBuffer(buffer, ret, i)
      })
    }

    const result = nestedUnrollBuffer(item, ret, 0)
    if (isPromise(result)) {
      return result.then(nestedItem => {
        buffer[i] = nestedItem
        return nestedUnrollBuffer(buffer, '', i)
      })
    }

    ret = result
  }

  return ret
}

export function unrollBuffer(buffer: SSRBuffer): Promise<string> | string {
  return nestedUnrollBuffer(buffer, '', 0)