A HelsinkiJS talk by Alex from https://starthq.com The video of this talk is available at http://youtu.be/pmyDJnEza6A

1. Server-Side JS @ StartHQ
Node, Fibers, Common Node etc.

2. Fibers
● lightweight threads
● co-operative multitasking
○ still using one event loop
● individual stack, shared heap
○ require a bit of additional memory for stacks
● similar to generators (in ES6)
○ but no need to mark each yielding method

3. Fibers usage example
function sleep(ms) {
var fiber = Fiber.current;
setTimeout(function() {
fiber.run();
}, ms);
Fiber.yield();
}

4. Sleep: Async. vs. Sync.
console.log('before');
setTimeout(function() {
console.log('after 1s');
}, 1000);
console.log('before');
sleep(1000);
console.log('after 1s');

5. CommonJS
● Set of specifications
○ Modules, Packages, Unit Testing
○ Binary, IO, Filesystem, JSGI, etc.
● Implemented by RingoJS and others
○ Ringo runs on top of the JVM
● Node supports the first 3, but not others
because they assume sync. I/O

6. Common Node
● Implements CommonJS specs using Fibers
on top of Node
● Allows for code reuse with RingoJS
● Simplifies business logic & debugging
○ supports for, exceptions etc. for flow control
● Performance: 80%-120% of Node
○ Uses a bit more memory e.g. 28MB vs. 32MB

7. Benchmarks

8. Node Streams
var body = [];
stream.on('data', function (chunk) {
body.push(chunk);
})
stream.on('end', function () {
callback(body);
});

9. Node Streams2
var body = [];
stream.on('readable', function () {
body.push(stream.read());
})
stream.on('end', function () {
callback(body);
});

10. Common Node Streams
var body = [], chunk;
while(chunk = stream.read(null)) {
body.push(chunk);
}
return body;
OR
return stream.read();

11. Ecosystem
● Ringo modules
● Common Utils
● Mongo Sync
● Stick
● Wrapping Node packages

12. Common Node at StartHQ
● Use it for everything
○ API, static resources
○ background processing
○ command line tools
● Extractors API
● Sentry stack traces

13. Pitfalls
● Trying to yield or resume outside fiber
● Using async libs with fibers, such as Express
● Writing to global variables
● Separate fiber instance per dependency
● Unreliable third party packages
○ Throws into event loop & crashed program

14. GitHub Links
● laverdet/node-fibers
● olegp/common-node
● olegp/notes
● starthq/extractor

15. Thank you!
@alexlamsl