Typedefs don't support "view" method in FastifyInstance

Prerequisites

[X] I have written a descriptive issue title
[X] I have searched existing issues to ensure the bug has not already been reported

Fastify version

4.4.0

Plugin version

No response

Node.js version

v14.15.1

Operating system

Windows

Operating system version (i.e. 20.04, 11.3, 10)

Description

The documentation says the following: The fastify object is decorated the same way as reply and allows you to just render a view into a variable instead of sending the result back to the browser:

But this is not described in the index.d.ts file, which is why the typescript compiler does not see the "view" method in FastifyInstance interface.

Solution: Extend FastifyInstance interface in index.d.ts

import { FastifyPlugin, FastifyReply, FastifyInstance, RawServerBase } from 'fastify';

declare module "fastify" {

  interface RouteSpecificOptions {
    layout?: string;
  }

  interface FastifyReply {
    view<T extends { [key: string]: any; }>(page: string, data: T, opts?: RouteSpecificOptions): FastifyReply;
    view(page: string, data?: object, opts?: RouteSpecificOptions): FastifyReply;
  }

  interface FastifyInstance {
    view<T extends { [key: string]: any; }, R>(page: string, data: T, opts?: RouteSpecificOptions): Promise<R>;
    view<R>(page: string, data?: object, opts?: RouteSpecificOptions): Promise<R>;
  }
}