Added to node.js notes

nodejs.md

@@ -1,10 +1,68 @@
 # NodeJS
 
-## Debugging node.js
+https://blog.heroku.com/archives/2015/11/10/node-habits-2016
+
+## Learning
+- https://nodeschool.io/
+- http://exercism.io/languages/javascript
+
+## Debugging
+**debug-options**  
+The `node` binary has *tons* of options to play with
+```shell
+node --optimize_for_size --max_old_space_size=920 --gc_interval=100
+node --prof-process --perf_basic_prof --trace-gc --abort-on-uncaught-exception
+```
+
+### Modules
+There are a number of modules you should check out for debugging your node.js application. I use `heapdump`,`blocked` & `memwatch` in production with an endpoint
+to get stats and trigger dumps to debug production apps.
+
+```javascript
+'use strict';
+
+// Ideally you have an endpoint that only accepts localhost
+// requests to trigger a heapdump
+const heapdump = require('heapdump');
+const blocked  = require('blocked');
+const memwatch = require('memwatch');
+const gc       = require('gc-stats');
+const procfs   = require('procfs-stats');
+
+const ps = procfs(process.pid);
+
+ps.io(function(err,io){
+  console.log('my process has done this much io', io);
+});
+
+ps.stat(function(err,io){
+  console.log('my process has done this much io', io);
+});
+
+gc.on('stats', function (stats) {
+  console.log('GC happened', stats);
+});
+
+```
+
+### Performance
+
+```shell
+gcore `pgrep node`  # core dump for mdb?
+perf record -F 99 -p `pgrep -n node` -g -- sleep 30
+```
+
+
+### Links
+- https://nodejs.org/en/blog/uncategorized/profiling-node-js/
+- https://github.com/joyent/node-stackvis
+- https://github.com/chrisa/node-dtrace-provider
+- https://www.npmjs.com/package/appmetrics
 - http://techblog.netflix.com/2014/11/nodejs-in-flames.html
 - https://nodejs.org/en/docs/guides/simple-profiling/
 - https://blog.heroku.com/node-habits-2016
 - http://www.slideshare.net/yunongx/debugging-node-in-prod
 - https://github.com/node-inspector/v8-profiler
 - https://blog.risingstack.com/finding-a-memory-leak-in-node-js/
-- http://www.brendangregg.com/blog/2014-09-17/node-flame-graphs-on-linux.html
+- http://www.brendangregg.com/blog/2014-09-17/node-flame-graphs-on-linux.html
+