server.js

'use strict'
const render = require('./lib/render');
const logger = require('koa-logger');
const router = require('koa-router')();
const koaBody = require('koa-body');

const Koa = require('koa');
const app = new Koa();

const posts = [];

// middleware
app.use(logger());

app.use(render);

app.use(koaBody());

// route definitions
router.get('/', list)
    .get('/post/new', add)
    .get('/post/:id', show)
    .post('/post', create);

app.use(router.routes());

async function list(ctx) {
    await ctx.render('list', { posts: posts });
}

async function add(ctx) {
    await ctx.render('new');
}

async function show(ctx) {
    const id = ctx.params.id;
    const post = posts[id];
    if (!post) ctx.throw(404, 'invalid post id');
    await ctx.render('show', { post: post });
}

async function create(ctx) {
    const post = ctx.request.body;
    const id = posts.push(post) - 1;
    post.created_at = new Date();
    post.id = id;
    ctx.redirect('/');
}

// listen
app.listen(3000);