#Middleware

@esmx/core exposes a small set of connect-style middleware helpers used to serve a module's static assets (the built dist/client output) with correct cache headers. These are what esmx.middleware is built from, and you can compose them directly when wiring your own HTTP server.

#Middleware

type Middleware = (
    req: IncomingMessage,
    res: ServerResponse,
    next: Function
) => void;

A connect-style middleware: it receives the Node request and response plus a next callback, and either handles the request or calls next() to pass control on. It is compatible with http, Express, Koa (via adapters), and most Node servers.

const loggerMiddleware: Middleware = (req, res, next) => {
    console.log(`${req.method} ${req.url}`);
    next();
};

#createMiddleware(esmx)

function createMiddleware(esmx: Esmx): Middleware;

Creates the middleware that serves static resources for every module in the Esmx instance. It:

• builds a static-file handler per module from the module configuration,
• applies cache control per request, and
• serves content-hashed (immutable) files with long-lived caching.

import { Esmx, createMiddleware } from '@esmx/core';

const esmx = new Esmx();
const middleware = createMiddleware(esmx);

// Use it in any Node HTTP server
server.use(middleware);

#mergeMiddlewares(middlewares)

function mergeMiddlewares(middlewares: Middleware[]): Middleware;

Composes an array of middlewares into a single middleware, running them in order until one handles the request or the chain ends (calling the outer next). Useful for combining createMiddleware's output with your own handlers.

import { mergeMiddlewares } from '@esmx/core';

const app = mergeMiddlewares([loggerMiddleware, createMiddleware(esmx)]);

#isImmutableFile(filename)

function isImmutableFile(filename: string): boolean;

Returns true when a file path matches Esmx's content-hashed (immutable) asset pattern — i.e. safe to serve with Cache-Control: public, max-age=31536000, immutable. createMiddleware uses it internally to decide the cache policy for each asset.

#Related

• Esmx — the core class whose middleware is composed from these helpers
• RenderContext — how rendered HTML references the assets these serve