Connect.Tech 2017: Stop JavaScripting Like It's 1999

Connect.Tech 2017: Stop JavaScripting Like It's 1999

1. 1. @hunterloftis Stop JavaScripting Like It’s 1999 Connect.Tech 2017
2. 2. @hunterloftis
3. 3. @hunterloftis
4. 4. @hunterloftis
5. 5. @hunterloftis
6. 6. @hunterloftis read package.json parse JSON fetch repository.url parse the body match “X users starred” in the body return the match 1 2 3 4 5 6 Fetching Stars
7. 7. @hunterloftis 1 2 3 4 5 6
8. 8. @hunterloftis Why would anyone use JavaScript?
9. 9. @hunterloftis !== blocking/slow 🐢concurrent/fast 🚗
10. 10. @hunterloftis concurrency tax
11. 11. @hunterloftis catch errors passed as arguments catch errors from rejected promises catch thrown errors blocking/slow 🐢concurrent/fast 🚗 create new execution contexts
12. 12. @hunterloftis That’s just how JavaScript works. worked
13. 13. @hunterloftis new tools for tax-free concurrency node >= 7.6.0 (Feb 22, 2017)
14. 14. @hunterloftis new tools for tax-free concurrency
15. 15. @hunterloftis So? There’s always something new in JavaScript.
16. 16. @hunterloftis 1. What does modern JS look like? 2. How can you start writing it? 3. Which obstacles should you expect?
17. 17. @hunterloftis 1. What does modern JS look like?
18. 18. @hunterloftis modern JS should read like Python concurrent/fast 🚗 …and run like JavaScript!
19. 19. @hunterloftis How?
20. 20. @hunterloftis Three Rules:
21. 21. @hunterloftis 1. Whenever you think about writing a callback, use async / await instead.
22. 22. @hunterloftis this is a callback function
23. 23. @hunterloftis 2. throw and catch Errors, or allow them to bubble. But otherwise leave them alone!
24. 24. @hunterloftis
25. 25. @hunterloftis “Pyramid of Doom” “Callback Hell”
26. 26. @hunterloftis 3.Instead of chaining Promises, use await + simple assignment.
27. 27. @hunterloftis
28. 28. @hunterloftis Is this still JavaScript? • no more callbacks • no more `if (err)` • no more Promises
29. 29. @hunterloftis The three objections
30. 30. @hunterloftis 1. I don’t understand async/await (which means I don’t understand Promises)
31. 31. @hunterloftis
32. 32. @hunterloftis “I return a Promise.” “I wait here for another Promise to resolve.” ?
33. 33. @hunterloftis
34. 34. @hunterloftis 2. Lots of modules still use callbacks (like node’s core APIs)
35. 35. @hunterloftisJune 2017: node-core Promises!
36. 36. @hunterloftisfor node < 8.0.0
37. 37. @hunterloftis 3. I work on a huge codebase (and rewrites are terrible)
38. 38. @hunterloftis
39. 39. @hunterloftis What does a modern foo look like?
40. 40. @hunterloftis async json = await… res = await… body = await… 1. no callbacks! 2. throw errors! 3. no chaining! what’s left?
41. 41. @hunterloftisPython
42. 42. @hunterloftis concurrent/fast 🚗 JavaScript
43. 43. @hunterloftis Before After
44. 44. @hunterloftis Questions? [email protected]