This Fetch API interface allows you to perform various actions on HTTP request and response headers. These actions include retrieving, setting, adding to, and removing. A Headers object has an associated header list, which is initially empty and consists of zero or more name and value pairs. You can add to this using methods like append() (see Examples). In all methods of this interface, header names are matched by case-insensitive byte sequence.
append(name: string,value: string,): void
Appends a new value onto an existing header inside a Headers object, or
adds the header if it does not already exist.
delete(name: string): void
Deletes a header from a Headers object.
get(name: string): string | null
Returns a ByteString sequence of all the values of a header within a
Headers object with a given name.
has(name: string): boolean
Returns a boolean stating whether a Headers object contains a certain
header.
set(name: string,value: string,): void
Sets a new value for an existing header inside a Headers object, or adds the header if it does not already exist.
getSetCookie(): string[]
Returns an array containing the values of all Set-Cookie headers
associated with a response.