https://github.com/serviejs/throwback

An asynchronous middleware pattern
https://github.com/serviejs/throwback

compose koa middleware popsicle servie

Last synced: 8 days ago
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An asynchronous middleware pattern

• Host: GitHub
• URL: https://github.com/serviejs/throwback
• Owner: serviejs
• License: mit
• Created: 2016-05-06T18:32:15.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2023-12-12T07:38:00.000Z (about 1 year ago)
• Last Synced: 2024-12-14T21:52:58.315Z (21 days ago)
• Topics: compose, koa, middleware, popsicle, servie
• Language: TypeScript
• Size: 1.5 MB
• Stars: 27
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Security: SECURITY.md

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README

        
# Throwback

[![NPM version](https://img.shields.io/npm/v/throwback.svg?style=flat)](https://npmjs.org/package/throwback)

[![NPM downloads](https://img.shields.io/npm/dm/throwback.svg?style=flat)](https://npmjs.org/package/throwback)

[![Build status](https://img.shields.io/travis/serviejs/throwback.svg?style=flat)](https://travis-ci.org/serviejs/throwback)

[![Test coverage](https://img.shields.io/coveralls/serviejs/throwback.svg?style=flat)](https://coveralls.io/r/serviejs/throwback?branch=master)

> Simple asynchronous middleware pattern.

## Installation

```

npm install throwback --save

```

## Usage

Compose asynchronous (promise-returning) functions.

```js

const { compose } = require("throwback");

const fn = compose([

  async function(ctx, next) {

    console.log(1);

    try {

      await next();

    } catch (err) {

      console.log("throwback", err);

    }

    console.log(4);

  },

  async function(ctx, next) {

    console.log(2);

    return next();

  }

]);

// Callback runs at the end of the stack, before

// the middleware bubbles back to the beginning.

fn({}, function(ctx) {

  console.log(3);

  ctx.status = 404;

});

```

**Tip:** In development (`NODE_ENV !== "production"`), `compose` will throw errors when you do something unexpected. In production, the faster non-error code paths are used.

### Example

Build a micro HTTP server!

```js

const { createServer } = require("http");

const finalhandler = require("finalhandler"); // Example only, not compatible with single `ctx` arg.

const { compose } = require("throwback");

const app = compose([

  function({ req, res }, next) {

    res.end("Hello world!");

  }

]);

createServer(function(req, res) {

  return app({ req, res }, finalhandler());

}).listen(3000);

```

## Use Cases

- HTTP requests (e.g. [`popsicle`](https://github.com/serviejs/popsicle))

- HTTP servers (e.g. [`servie`](https://github.com/serviejs/servie))

- Processing pipelines (e.g. [`scrappy`](https://github.com/blakeembrey/node-scrappy))

## Inspiration

Built for [`servie`](https://github.com/serviejs) and inspired by [`koa-compose`](https://github.com/koajs/compose).

## License

MIT