unexpected token error with Angular2

I was playing with Angular2 recently and it has been a quite enjoyful expeirence, until I ran into the ‘unexpected token <’ error:

uncaught SyntaxError: Unexpected token < - http:1
uncaught SyntaxError: Unexpected token < - angular2-polyfills.js:138
    evaluating http://localhost:3000/angular2/http
    error loading http://localhost:3000/app/boot.js

I spend some time to looking into the issue, and noticed that the response of http://localhost:3000/angular2/http is actually a html, not the right js file. I ran some search in Google and find that I am not alone. There are quite some questions in Stackoverflow for the same problem:

• Angular2 beta - bootstrapping HTTP_PROVIDERS - “Unexpected Token <”

Basically this is a problem about missing libraries. Some modules have to be added into html explicitly. I hope there is an easier way to figure out what need to be added when a class is used.

The following is the fix if you run into the same http issue:

# if npm is used
<script src="node_modules/angular2/bundles/http.dev.js"></script>
# if cdn is used
<script src="https://code.angularjs.org/2.0.0-beta.0/http.dev.js"></script>