gevorg gevorg - 6 months ago 122
Node.js Question

Can't run simple app with Koa v2

I am trying to run simple http server using Koa v2, but have problems running it.

It uses JavaScript syntax that is expected to work in future Node.js versions and I was wondering how can I run it with

node v6.1.0
?

index.js

import Koa from 'koa';
const app = new Koa();

// Setup handler.
app.use(async ctx => {
ctx.body = "Hello World!";
});

// Start server.
app.listen(3000);


I just need minimal steps that are required to make this server run with
node v6.1.0
.

execution

$ node --version
v6.1.0
$ node --harmony index.js
C:\Users\gevor\WebstormProjects\untitled1\index.js:1
(function (exports, require, module, __filename, __dirname) { import Koa from 'koa';
^^^^^^
SyntaxError: Unexpected token import
at exports.runInThisContext (vm.js:53:16)
at Module._compile (module.js:511:25)
at Object.Module._extensions..js (module.js:550:10)
at Module.load (module.js:456:32)
at tryModuleLoad (module.js:415:12)
at Function.Module._load (module.js:407:3)
at Function.Module.runMain (module.js:575:10)
at startup (node.js:160:18)
at node.js:445:3

Answer

I was able to find workaround and will describe solution that includes installing Babel module

Step 1: install Babel and required presets

$ npm install babel-core --save
$ npm install babel-preset-es2015-node5 --save
$ npm install babel-preset-stage-3 --save

Step 2: create index.js file with following content

// set babel in entry file
require('babel-core/register')({
    presets: ['es2015-node5', 'stage-3']
});

require('./app');

Step 3: put your server code inside app.js file

import Koa from 'koa';    
const app = new Koa();

// Setup handler.
app.use(async ctx => {
    ctx.body = "Hello World!";
});

// Start server.
app.listen(3000);

After running node index.js server works like a pie and import, async, await are being processed properly.

References

Comments