response.getHeader(name)

• name <string>
• 返回：数字 | 字符串 | 字符串[] | 未定义

读取已经排队但尚未发送给客户端的头部。名称不区分大小写。返回值的类型取决于提供给 response.setHeader() 的参数。

【Reads out a header that's already been queued but not sent to the client. The name is case-insensitive. The type of the return value depends on the arguments provided to response.setHeader().】

response.setHeader('Content-Type', 'text/html');
response.setHeader('Content-Length', Buffer.byteLength(body));
response.setHeader('Set-Cookie', ['type=ninja', 'language=javascript']);
const contentType = response.getHeader('content-type');
// contentType is 'text/html'
const contentLength = response.getHeader('Content-Length');
// contentLength is of type number
const setCookie = response.getHeader('set-cookie');
// setCookie is of type string[] 拷贝