Deploying unmodified reveal.js to Heroku - node.js

Question

I'm having trouble getting my reveal.js-based app to work on Heroku. I decided to step back and just try to get the vanilla reveal.js code successfully deployed to Heroku. I'm having trouble with that basic step. Heroku gives an:
Application error
An error occurred in the application and your page could not be served. If you are the application owner, check your logs for details.
I followed the Getting Started on Heroku with Node.js guide, but grabbed the reveal.js code from GitHub using the Full setup Readme steps. Here are the steps I followed along with the results from the Terminal:
$ git clone https://github.com/hakimel/reveal.js.git
Cloning into 'reveal.js'...
remote: Counting objects: 10252, done.
remote: Total 10252 (delta 0), reused 0 (delta 0), pack-reused 10252
Receiving objects: 100% (10252/10252), 7.58 MiB | 6.55 MiB/s, done.
Resolving deltas: 100% (5644/5644), done.
$ ls
moac-node-reveal moac-solo-with-php reveal.js
$ cd reveal.js/
$ ls
CONTRIBUTING.md LICENSE bower.json demo.html js package.json test
Gruntfile.js README.md css index.html lib plugin
$ npm install
npm WARN deprecated coffee-script#1.10.0: CoffeeScript on NPM has moved to "coffeescript" (no hyphen)
npm WARN deprecated http2#3.3.7: Use the built-in module in node 9.0.0 or newer, instead
> node-sass#4.7.2 install /Users/simon/code/reveal.js/node_modules/node-sass
> node scripts/install.js
Cached binary found at /Users/simon/.npm/node-sass/4.7.2/darwin-x64-59_binding.node
> phantomjs-prebuilt#2.1.16 install /Users/simon/code/reveal.js/node_modules/phantomjs-prebuilt
> node install.js
PhantomJS not found on PATH
Download already available at /var/folders/0n/rj76dqgx3yvd2tph37qlyvsm0000gn/T/phantomjs/phantomjs-2.1.1-macosx.zip
Verified checksum of previously downloaded file
Extracting zip contents
Removing /Users/simon/code/reveal.js/node_modules/phantomjs-prebuilt/lib/phantom
Copying extracted folder /var/folders/0n/rj76dqgx3yvd2tph37qlyvsm0000gn/T/phantomjs/phantomjs-2.1.1-macosx.zip-extract-1514746311473/phantomjs-2.1.1-macosx -> /Users/simon/code/reveal.js/node_modules/phantomjs-prebuilt/lib/phantom
Writing location.js file
Done. Phantomjs binary available at /Users/simon/code/reveal.js/node_modules/phantomjs-prebuilt/lib/phantom/bin/phantomjs
> node-sass#4.7.2 postinstall /Users/simon/code/reveal.js/node_modules/node-sass
> node scripts/build.js
Binary found at /Users/simon/code/reveal.js/node_modules/node-sass/vendor/darwin-x64-59/binding.node
Testing binary
Binary is fine
npm notice created a lockfile as package-lock.json. You should commit this file.
added 473 packages in 13.798s
╭─────────────────────────────────────╮
│ │
│ Update available 5.5.1 → 5.6.0 │
│ Run npm i -g npm to update │
│ │
╰─────────────────────────────────────╯
$ npm start
> reveal.js#3.6.0 start /Users/simon/code/reveal.js
> grunt serve
(node:7173) ExperimentalWarning: The http2 module is an experimental API.
Running "connect:server" (connect) task
Started connect web server on http://localhost:8000
Running "watch" task
Waiting...
^C
╭─────────────────────────────────────╮
│ │
│ Update available 5.5.1 → 5.6.0 │
│ Run npm i -g npm to update │
│ │
╰─────────────────────────────────────╯
$ heroku login
Enter your Heroku credentials:
Email: redacted#email.address
Password: **************
Two-factor code: ******
Logged in as redacted#email.address
$ node -v
v9.3.0
$ npm -v
5.5.1
$ git --version
git version 2.14.3 (Apple Git-98)
$ heroku create
Creating app... done, ⬢ calm-crag-42588
https://calm-crag-42588.herokuapp.com/ | https://git.heroku.com/calm-crag-42588.git
$ git push heroku master
Counting objects: 10020, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (3988/3988), done.
Writing objects: 100% (10020/10020), 7.43 MiB | 677.00 KiB/s, done.
Total 10020 (delta 5525), reused 10020 (delta 5525)
remote: Compressing source files... done.
remote: Building source:
remote:
remote: -----> Node.js app detected
remote:
remote: -----> Creating runtime environment
remote:
remote: NPM_CONFIG_LOGLEVEL=error
remote: NPM_CONFIG_PRODUCTION=true
remote: NODE_VERBOSE=false
remote: NODE_ENV=production
remote: NODE_MODULES_CACHE=true
remote:
remote: -----> Installing binaries
remote: engines.node (package.json): >=4.0.0
remote: engines.npm (package.json): unspecified (use default)
remote:
remote: Resolving node version >=4.0.0...
remote: Downloading and installing node 9.3.0...
remote: Using default npm version: 5.5.1
remote:
remote: -----> Restoring cache
remote: Skipping cache restore (not-found)
remote:
remote: -----> Building dependencies
remote: Installing node modules (package.json)
remote: up to date in 0.09s
remote:
remote: -----> Caching build
remote: Clearing previous node cache
remote: Saving 2 cacheDirectories (default):
remote: - node_modules (nothing to cache)
remote: - bower_components (nothing to cache)
remote:
remote: -----> Build succeeded!
remote: -----> Discovering process types
remote: Procfile declares types -> (none)
remote: Default types for buildpack -> web
remote:
remote: -----> Compressing...
remote: Done: 18.7M
remote: -----> Launching...
remote: Released v3
remote: https://calm-crag-42588.herokuapp.com/ deployed to Heroku
remote:
remote: Verifying deploy... done.
To https://git.heroku.com/calm-crag-42588.git
* [new branch] master -> master
$ heroku ps:scale web=1
Scaling dynos... done, now running web at 1:Free
$ heroku open
$ heroku logs
2017-12-31T18:55:41.167608+00:00 app[api]: Release v2 created by user redacted#email.address
2017-12-31T18:55:40.984802+00:00 app[api]: Release v1 created by user redacted#email.address
2017-12-31T18:55:40.984802+00:00 app[api]: Initial release by user redacted#email.address
2017-12-31T18:55:41.167608+00:00 app[api]: Enable Logplex by user redacted#email.address
2017-12-31T18:56:13.000000+00:00 app[api]: Build started by user redacted#email.address
2017-12-31T18:56:20.523781+00:00 app[api]: Scaled to web#1:Free by user redacted#email.address
2017-12-31T18:56:20.502923+00:00 app[api]: Release v3 created by user redacted#email.address
2017-12-31T18:56:20.502923+00:00 app[api]: Deploy a0c01360 by user redacted#email.address
2017-12-31T18:56:13.000000+00:00 app[api]: Build succeeded
2017-12-31T18:56:22.217173+00:00 heroku[web.1]: Starting process with command `npm start`
2017-12-31T18:56:24.295551+00:00 app[web.1]: > reveal.js#3.6.0 start /app
2017-12-31T18:56:24.295401+00:00 app[web.1]:
2017-12-31T18:56:24.295552+00:00 app[web.1]: > grunt serve
2017-12-31T18:56:24.295553+00:00 app[web.1]:
2017-12-31T18:56:24.306026+00:00 app[web.1]: sh: 1: grunt: not found
2017-12-31T18:56:24.310223+00:00 app[web.1]: npm ERR! file sh
2017-12-31T18:56:24.310226+00:00 app[web.1]: npm ERR! code ELIFECYCLE
2017-12-31T18:56:24.310227+00:00 app[web.1]: npm ERR! errno ENOENT
2017-12-31T18:56:24.310228+00:00 app[web.1]: npm ERR! syscall spawn
2017-12-31T18:56:24.311279+00:00 app[web.1]: npm ERR! reveal.js#3.6.0 start: `grunt serve`
2017-12-31T18:56:24.311803+00:00 app[web.1]: npm ERR! Failed at the reveal.js#3.6.0 start script.
2017-12-31T18:56:24.311414+00:00 app[web.1]: npm ERR! spawn ENOENT
2017-12-31T18:56:24.311669+00:00 app[web.1]: npm ERR!
2017-12-31T18:56:24.311943+00:00 app[web.1]: npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
2017-12-31T18:56:24.317995+00:00 app[web.1]: npm WARN Local package.json exists, but node_modules missing, did you mean to install?
2017-12-31T18:56:24.318729+00:00 app[web.1]:
2017-12-31T18:56:24.318964+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2017-12-31T18:56:24.319122+00:00 app[web.1]: npm ERR! /app/.npm/_logs/2017-12-31T18_56_24_313Z-debug.log
2017-12-31T18:56:27.086467+00:00 heroku[web.1]: Starting process with command `npm start`
2017-12-31T18:56:24.393036+00:00 heroku[web.1]: Process exited with status 1
2017-12-31T18:56:24.405623+00:00 heroku[web.1]: State changed from starting to crashed
2017-12-31T18:56:24.407532+00:00 heroku[web.1]: State changed from crashed to starting
2017-12-31T18:56:30.585270+00:00 heroku[web.1]: State changed from starting to crashed
2017-12-31T18:56:30.556563+00:00 heroku[web.1]: Process exited with status 1
2017-12-31T18:56:30.393715+00:00 app[web.1]:
2017-12-31T18:56:30.393731+00:00 app[web.1]: > reveal.js#3.6.0 start /app
2017-12-31T18:56:30.393732+00:00 app[web.1]: > grunt serve
2017-12-31T18:56:30.393732+00:00 app[web.1]:
2017-12-31T18:56:30.400445+00:00 app[web.1]: sh: 1: grunt: not found
2017-12-31T18:56:30.404923+00:00 app[web.1]: npm ERR! file sh
2017-12-31T18:56:30.405234+00:00 app[web.1]: npm ERR! code ELIFECYCLE
2017-12-31T18:56:30.405479+00:00 app[web.1]: npm ERR! errno ENOENT
2017-12-31T18:56:30.405725+00:00 app[web.1]: npm ERR! syscall spawn
2017-12-31T18:56:30.409574+00:00 app[web.1]: npm ERR! reveal.js#3.6.0 start: `grunt serve`
2017-12-31T18:56:30.409737+00:00 app[web.1]: npm ERR! spawn ENOENT
2017-12-31T18:56:30.410022+00:00 app[web.1]: npm ERR!
2017-12-31T18:56:30.410205+00:00 app[web.1]: npm ERR! Failed at the reveal.js#3.6.0 start script.
2017-12-31T18:56:30.410375+00:00 app[web.1]: npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
2017-12-31T18:56:30.428235+00:00 app[web.1]: npm WARN Local package.json exists, but node_modules missing, did you mean to install?
2017-12-31T18:56:30.429020+00:00 app[web.1]:
2017-12-31T18:56:30.429211+00:00 app[web.1]: npm ERR! A complete log of this run can be found in:
2017-12-31T18:56:30.429337+00:00 app[web.1]: npm ERR! /app/.npm/_logs/2017-12-31T18_56_30_412Z-debug.log
2017-12-31T18:56:36.818819+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=calm-crag-42588.herokuapp.com request_id=8b23ad0b-29bd-4a6a-bbf8-cd991fdc334a fwd="47.32.63.6" dyno= connect= service= status=503 bytes= protocol=https
2017-12-31T18:56:37.254436+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=calm-crag-42588.herokuapp.com request_id=8267e9aa-69ca-4998-b967-89e1db724b30 fwd="47.32.63.6" dyno= connect= service= status=503 bytes= protocol=https

Answer 1

Two things fixed this:
1. package.json: moved devDependencies to dependencies
"devDependencies": {
"express": "^4.16.2",
"grunt": "^1.0.1",
"grunt-autoprefixer": "^3.0.4",
"grunt-cli": "^1.2.0",
"grunt-contrib-connect": "^1.0.2",
"grunt-contrib-cssmin": "^2.2.1",
"grunt-contrib-jshint": "^1.1.0",
"grunt-contrib-qunit": "^1.2.0",
"grunt-contrib-uglify": "^2.3.0",
"grunt-contrib-watch": "^1.0.0",
"grunt-retire": "^1.0.7",
"grunt-sass": "^2.0.0",
"grunt-zip": "^0.17.1",
"mustache": "^2.3.0",
"socket.io": "^1.7.4"},
...became:
"devDependencies": {},
And:
"dependencies": {
"reveal-ga": "^0.1.0"}
...became:
"dependencies": {
"reveal-ga": "^0.1.0",
"express": "^4.16.2",
"grunt": "^1.0.1",
"grunt-autoprefixer": "^3.0.4",
"grunt-cli": "^1.2.0",
"grunt-contrib-connect": "^1.0.2",
"grunt-contrib-cssmin": "^2.2.1",
"grunt-contrib-jshint": "^1.1.0",
"grunt-contrib-qunit": "^1.2.0",
"grunt-contrib-uglify": "^2.3.0",
"grunt-contrib-watch": "^1.0.0",
"grunt-retire": "^1.0.7",
"grunt-sass": "^2.0.0",
"grunt-zip": "^0.17.1",
"mustache": "^2.3.0",
"socket.io": "^1.7.4"}
Gruntfile.js: use $PORT environment variable
var port = grunt.option('port') || 8000;
...became:
var port = grunt.option('port') || process.env.PORT || 8000;