Javascript Promises

Lightning talk about Promises @ SorocabaJs

Transcript

1. promises && js2015 felipe bernardes github.com/felipebernardes
2. http://felipebernardes.github.io #votorantim http://tegra.me 2
4. execution stack && contexts
6. console.log(‘1’); setTimeout(() => console.log(‘2’), 0); console.log(‘3’); setTimeout(() => console.log(‘4’), 1000); //1324
7. why promise?
9. • no more callback hell || pyramid of d00m ◦ better performance • cleaner && less code ◦ better to undestand ◦ easier to maintain ◦ responsabilities && modularization • better error handling
10. why not promise?
12. how to promise
13. doThis(param) .then( response => this.someAttr = param);
14. ( ... ) //syncronous code doThis(param) .then( response => this.someAttr = param); ( ... ) //syncronous code
15. doThis(param) .then( response => this.someAttr = param) .catch ( errorResponse => console.log(errorResponse) );
16. all && race
17. all http://jsfiddle.net/jsengel/mc3p01nb/ then after all promises returned, catch if any of them fails
18. race then after one of the promises returns, catch if any of them fails
19. var p3 = new Promise(function(resolve, reject) { setTimeout(resolve, 100, "three"); }); var p4 = new Promise(function(resolve, reject) { setTimeout(reject, 500, "four"); }); Promise.race([p3, p4]).then(function(value) { console.log(value); //three }
20. example
21. const setStatus = (group, status) => { const data = { status: status, shopId: group.shop.id, }; return $http.post(`${API}/group/${group.id}/shop/status`, data); }; // service
22. ShopListService.setStatus(this.group, 'closed') .then( () => this.group.shop.status = 'closed'); // controller
24. further reading
25. articles
26. html5rocks http://www.html5rocks.com/en/tutorials/es6/promises nomadev http://nomadev.com.br/angularjs-promises-promessas-o-guia- definitivo/ david walsh https://davidwalsh.name/write-javascript-promises
27. libs
28. $q https://github.com/kriskowal/q bluebird http://bluebirdjs.com/
29. python sorocaba - https://groups.google.com/forum/m/#!forum/python-sorocaba guru sorocaba - https://www.facebook.com/GURUSorocaba/ hacklab - https://www.facebook.com/hacklabsorocaba/ GDG Sorocaba - https://www.facebook.com/GDGSorocaba/ SorocabaJS - https://www.facebook.com/sorocabajs/ JS Meetup - http://www.meetup.com/GDG-Sorocaba/ WomenTechmakers - https://www.facebook.com/groups/wtmsorocaba/ in.tegra.do - http://www.meetup.com/In-Tegra-Do/ english meetup - http://www.meetup.com/Sorocaba-English-Conversation-Happy-Hours/ #chegaMais
30. we're hiring estagio@tegra.me vagas@tegra.me
31. co-authored by felipe l. soares caique mitsuoka jean vitor
32. speakerdeck.com/felipebernardes valeu!