Function formatResponse

packages/res/src/format.ts:22–51

(
  req: Request,
  res: Response,
  next: Next
)

type Req = Pick<I, 'headers'>

export const formatResponse = <Request extends Req = Req, Response extends Res = Res, Next extends next = next>(
  req: Request,
  res: Response,
  next: Next
) => (obj: FormatProps) => {
  const fn = obj.default

  if (fn) delete obj.default

  const keys = Object.keys(obj)

  const key = keys.length > 0 ? (getAccepts(req)(...keys) as string) : false

  setVaryHeader(res)('Accept')

  if (key) {
    res.setHeader('Content-Type', normalizeType(key).value)
    obj[key](req, res, next)
  } else if (fn) {
    fn()
  } else {
    const err = new Error('Not Acceptable') as FormatError
    err.status = err.statusCode = 406
    err.types = normalizeTypes(keys).map((o) => o.value)

    next(err)
  }

  return res
}