snuji

snuji is a context-based middleware implementation.

Installation

yarn add snuji

or

npm install --save snuji

Usage

import compose, { Middlware, Handler } from "snuji";

// Define your shared middleware context
type Context = { value: number };

// Define your middleware; each can modify the context before,
// and after, the next middleware in the chain resolves.
const middleware: Middleware<Context>[] = [
    async (ctx, next) => {
        console.debug("Middleware 1 Start");
        ctx.value += 1;
        await next();
        console.debug("Middleware 1 End");
    },
    async (ctx, next) => {
        console.debug("Middleware 2 Start");
        ctx.value += 1;
        await next();
        console.debug("Middleware 2 End");
    }
];

// In an application create your context and run your
// middleware stack, and pass the context to your handler.

// In your application…
(async () => {
    // Instantiate your context
    const ctx: Context = { value: 0 };

    // Compose your middleware
    const stack = compose<Context>(...middleware);

    // Define your handler to be sandwiched by your middleware
    const handler: Handler<Context> = ctx => console.log("Value: " + ctx.value);

    // Pass your context through the middleware and handler stack.
    await stack(ctx, handler);

    // The mutated context is still available after the stack.
})();

// Output:
// Middleware 1 Start
// Middleware 2 Start
// Value: 2
// Middleware 2 End
// Middleware 1 End

Prior Art

This package is based on the middleware implementation included in koa.

What does "snuji" mean?

It's a Lojban gismu.