Function TypedHeaders

Type safe HTTP headers decorator.

TypedHeaders is a decorator function that can parse HTTP headers. It is almost same with nest.Headers, but it can automatically cast property type following its DTO definition. Also, TypedHeaders performs type validation.

For reference, target type T must follow such restrictions. Also, if actual HTTP header values are different with their promised type T, BadRequestException error (status code: 400) would be thrown.

1. Type T must be an object type
2. Do not allow dynamic property
3. Property key must be lower case
4. Property value cannot be null, but undefined is possible
5. Only boolean, bigint, number, string or their array types are allowed
6. By the way, union type never be not allowed
7. Property set-cookie must be array type
8. Those properties cannot be array type

• Age
• Authorization
• Content-length
• Content-type
• Etag
• Expires
• From
• Host
• If-modified-since
• If-unmodified-since
• Last-modified
• Location
• Max-forwards
• Proxy-authorization
• Referer
• Retry-after
• Server
• User-agent