Optionalfetch
fetch?: { 
    (input: RequestInfo | URL, init?: RequestInit): Promise<Response>; 
    (input: string | Request | URL, init?: RequestInit): Promise<Response>; 
}
Type declaration
- (input, init?): Promise<Response>
 Parameters
- input: RequestInfo | URL
 Optionalinit: RequestInit
Returns Promise<Response>
- (input, init?): Promise<Response>
 Parameters
- input: string | Request | URL
 Optionalinit: RequestInit
Returns Promise<Response>
MDN Reference