Decorating App Router Route Handlers (next.js)

handlerClass.ts

class HawkExperiment
{
    async getEndpoint(request: Request, params: any)
    {
        // headers = array of key value pairs extracted from headers
        let headers: {[p: string]: string} = {}
        request.headers.forEach((val, key, allHeaders) => {
            headers[key] = val
        })
        return Response.json({
            headers: headers,
            params
        })
    }

    async postEndpoint(request: Request, params: any){
        let headers: Record<string, string> = {}
        request.headers.forEach((val, key, allHeaders) => {
            headers[key] = val
        })

        const data = request.formData()

        return Response.json({
            headers: headers,
            body: params
        })
    }
}

function handler(cls: new () => any) {
    const instance = new cls()
    let routes: { GET?: any, POST?: any } = {}
    if (instance.getEndpoint) {
        routes.GET = instance.getEndpoint
    }
    if (instance.postEndpoint) {
        routes.POST = instance.postEndpoint
    }
    return routes
}

const { GET, POST } = handler(HawkExperiment)

export {
    GET,
    POST
}

route.ts

/**
 * With the previous file deployed in a catch-all route, the handler can be deployed to handle sub-routes,
 * but this special wrapper should be required to make use of the top-level route.
 */

import { GET, POST } from './[...sub]/route'

export {
    GET,
    POST
}