# express-coroutine

**Repository Path**: yourtion/express-coroutine

## Basic Information

- **Project Name**: express-coroutine
- **Description**: 在 Express 中像 Koa 那样使用 Generator 方法
- **Primary Language**: NodeJS
- **License**: MIT
- **Default Branch**: master
- **Homepage**: https://github.com/yourtion/express-coroutine
- **GVP Project**: No

## Statistics

- **Stars**: 2
- **Forks**: 0
- **Created**: 2017-03-01
- **Last Updated**: 2020-12-18

## Categories & Tags

**Categories**: webframework

**Tags**: None

## README

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[![David deps][david-image]][david-url]
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[![npm license][license-image]][download-url]
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[npm-url]: https://npmjs.org/package/express-coroutine
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# express-coroutine

Generator function and Async function to be used as middlewares in express like koa. ( use [lei-coroutine](https://github.com/leizongmin/lei-coroutine) )

## Installation

```bash
npm install express-coroutine --save
```

## Usage

### Init express

```javascript
const express = require('express-coroutine')(require('express'));
const app = express();
```

### Init router

```javascript
const express = require('express-coroutine')(require('express'));
const app = express();
const router = new express.Router();
app.use(router);

router.get('/', function* (req, res) {
  res.send('it works!');
});

// also async function
router.get('/', async function (req, res) {
  res.send('it works!');
});
```

Write your express routes by using generator functions as middlewares. 

```javascript
const express = require('express-coroutine')(require('express'));

const app = express();

app.get('/user/:id', function* (req, res) {
  const user = yield User.findById(req.params.id);
  res.send(user);
})

app.get('/error', function* (req, res) {
  throw new Error('Bang!');
});

// also async function
app.get('/user2/:id', async function* (req, res) {
  const user = await User.findById(req.params.id);
  res.send(user);
});

app.listen(8000);
```

You can also define multiple generator functions just the express way.

```javascript
const fn = function (req, res, next) {
  return new Promise((resolve, reject) => {
    if (req.params.user !== 'a') return reject(new Error('Bang!'));
    resolve('a');
  });
};

const middleware = function* (req, res, next) {
  yield fn(req, res, next);
};

const middleware2 = async function (req, res, next) {
  await fn(req, res, next);
  next();
};

app.get('/:user', middleware, function* (req, res) {
  res.send('it works!');
});

app.get('/:user', middleware2, async function (req, res) {
  res.send('it works!');
});
```

More detail demo can be found in [test.js](test.js)

### Get coroutine

```javascript
const coroutine = require('express-coroutine').coroutine;
```