index.js

import fastify from 'fastify';
import fastifyBabel from 'fastify-babel';
import fastifyStatic from '@fastify/static';
import fastifyHttpProxy from '@fastify/http-proxy';

export class FastifyIntegrationDaemon {
    constructor(fastifyOptions) {
        this.daemon = fastify(fastifyOptions);
    }

    serveProxy({prefix, upstream, onResponse}) {
        const replyOptions = onResponse ? {onResponse} : undefined;
        this.daemon.register(fastifyHttpProxy, {
            upstream: `${upstream}${prefix}`,
            prefix,
            replyOptions
        });

        return this;
    }

    forwardWS({path, destination}) {
        this.daemon.register(fastifyHttpProxy, {
            websocket: true,
            prefix: path,
            upstream: destination,
            wsUpstream: destination
        });

        return this;
    }

    serveBuilt({prefix, root}) {
        this.daemon.register((fastify, options, next) => {
            fastify
                .register(fastifyStatic, {
                    root,
                    redirect: true
                })
                .setNotFoundHandler((_, reply) => reply.sendFile('index.html'));

            next();
        }, {prefix});

        return this;
    }

    serveSource({prefix, root, manifest, nodeModules, babelrc}) {
        const babelCache = new Map();
        this.daemon.get('/purge-cache', (_, reply) => {
            const message = `Cleared ${babelCache.size} entries`;
            babelCache.clear();
            console.log(message);
            reply.send(`${message}\n`);
        });

        this.daemon.register((fastify, options, next) => {
            fastify
                .register((fastify, options, next) => {
                    fastify.register(fastifyStatic, {
                        root,
                        redirect: true
                    });
                    fastify.get('/manifest.webmanifest', (_, reply) => reply.send(manifest));
                    fastify.setNotFoundHandler((_, reply) => reply.sendFile('index.html'));

                    next();
                }, {prefix})
                .register(fastifyStatic, {
                    prefix: '/node_modules',
                    root: nodeModules,
                    decorateReply: false
                })
                .register(fastifyBabel, {
                    babelrc,
                    maskError: false,
                    cache: babelCache
                });

            next();
        });

        return this;
    }

    listen(...args) {
        return this.daemon.listen(...args);
    }

    unref() {
        this.daemon.server.unref();
    }

    address() {
        return this.daemon.server.address();
    }
}