Why is Heroku not detecting my start script? - node.js

Question

I have a Node.js application on Heroku. To start it, I need index.jsto be executed. To do that, I added a package.json file with a start script.
As I read in Heroku Node.js Support:
First, Heroku looks for a Procfile specifying your process types.
If no Procfile is present in the root directory of your app during the build process, your web process will be started by running npm start, a script you can specify in package.json...
When I define the start script to be node index.js and I deploy my app to Heroku, I don't see any Dynos in the resources tab.
My code:
package.json
{
"name": "node.js app",
"version": "1.4.0",
"description": "A node.js app.",
"main": "index.js",
"repository": {
"type": "git",
"url": "Node.js repository"
},
"author": "Realex78",
"license": "MPL-2.0",
"dependencies": {
"npm package": "^1.0.0"
},
"devDependencies": {
"npm package": "^1.0.0"
},
"scripts": {
"start": "node index.js",
"poststart": "node scripts/poststart.js",
"restart": "node scripts/restart.js"
}
}

Answer 1

Make sure that you aren't using a Procfile, as Heroku gives it priority over package.json!
I.e. even though I had updated my startup script in package.json:
"scripts": {
"start": "node --harmony server.js"
},
I had forgotten that my Procfile was setup like this:
web: node server.js
Therefore my startup script in package.json was being ignored! The fix was to update my Procfile (to in this case include the --harmony param).
Note that I did not have to wait 24 hours for a successful deploy; it worked immediately.