Callbags

Introduction to the "callbags" specification for lightweight observables & iterables.

Transcript

1. Callbags BY STEPHAN SCHNEIDER
2. “Didn’t you mean ‘callbacks’” Literally everyone I told about this talk
3. What are callbags? • a contract how callbacks work in their context • similar to Node's error-first convention // error-first fs.readFile('/path/to/file', (err, data) => { ... }) // callbag source(0, (type, data) => { ... })
4. Generality Promise Observable Callbag Function Where does it stand?
5. Predictability Promise Observable Callbag Function Where does it stand?
6. The specification https://github.com/callbag/callbag
7. Sources - produces data Terms → Sinks - consumes data → Operators - takes a source, returns a source →
8. (type: number, payload?: any) => void
9. “End” - terminate the callbag “Start” - sent & received once as part of the handshake Design Principles 0 2 Type 1 “Data” - deliver data to the callbag
10. • Call source with type === 0 • Callback is greeted back with type === 0 • “Talkback” allows sending data to source Handshake
11. • type === 2 • Without second parameter: success • Anything truthy as second parameter: error Termination
12. • type === 1 • Only after handshake • Only before termination Data Delivery
13. “A standard for JS callbacks that enables lightweight observables and iterables”
14. Let’s have a look at the code
15. • No central implementation • Anything that sticks to the interface is considered a callback • There’s no official standard lib • Everyone is invited to become an operator maintainer Governance
16. Further reading • Spec: https://github.com/callbag/callbag • Comparison to RxJS: https://egghead.io/articles/comparing-callba gs-to-rxjs-for-reactive-programming
17. Further reading • Wiki: https://github.com/callbag/callbag/wiki (contains a list of available utility packages) • Toolkit of commonly used operators: https://github.com/staltz/callbag-basics