outgoingMessage.hasHeader(name)

• name <string>
• 返回 <boolean>

如果 name 标识的标头当前设置在传出标头中，则返回 true。 标头名称不区分大小写。

const hasContentType = outgoingMessage.hasHeader('content-type');

• name <string>
• Returns <boolean>

Returns true if the header identified by name is currently set in the outgoing headers. The header name is case-insensitive.

const hasContentType = outgoingMessage.hasHeader('content-type');