Off the Rails

My journey to becoming a
~hipster~ Node.js developer

Transcript

1. Off the Rails My journey to becoming a hipster Node.js developer
2. Hi, I’m Dan
3. Ruby is my first love
4. But I got into an affair with Node.js
5. Temptation
6. Client said they had “experience”
7. (also didn’t seem to like ruby for some reason)
8. But what the heck, Node.js is the new hotness, right?
10. First rule of node.js -
11. THERE ARE NO RULES!
12. Seeing a node.js project for the first time
13. Controllers?
14. Express.js !
15. Models?
16. Find an ORM that works!
17. Views?
18. $ mkdir views $ vim views/index.jade
19. No Black Magic
20. Just raw, naked programming
21. Make your OWN conventions
23. “What happens server-side, stays server side” Problem?
24. Scenario: Developer A types in a ‘console.log’
25. Developer B: “where is that going to show up?”
26. Developer B: “where is that going to show up?” Developer A: “in the server log”
27. Developer B: “where is that going to show up?” Developer A: “in the server log” Developer B: “okay cool”
28. Developer B: “where is that going to show up?” Developer A: “in the server log” Developer B: “okay cool” both devs watch the server log for some time
29. Developer B: “where is that going to show up?” Developer A: “in the server log” Developer B: “okay cool” both devs watch the server log for some time Developer A: “No wait, there it is in Chrome’s devtools"
30. Familiar (but different)
31. npm / bundler
32. gulp / rake
33. ndenv / rbenv
34. mocha / rspec
35. jade / slim
36. Express.js / sinatra
37. Sequelize / ActiveRecord (almost)
38. factory-girl / factory-girl
39. Going so fast!
40. WHY SO SYNCHRONOUS?
41. Errorbacks
42. Errorbacks
43. The anatomy of an ‘errorback’ function(error, results…)
44. The anatomy of an ‘errorback’ function(error, results…) the result(s) of the function taking the callback
45. The anatomy of an ‘errorback’ function(error, results…) this is non-null if there was an error the result(s) of the function taking the callback
46. foo(42, function(err, result) { // happens “later” if (err) { console.error(err.message); } else { console.log(result); } }); // happens immediately ...
47. Seems innocent enough until ...
48. Callback Hell
49. foo(42, function(err, fooResult) { if (!err) { bar(fooResult, function(err, barResult) { if (!err) { baz(barResult, function(err, bazResult) { if (!err) { qux(bazResult, function(err, quxResult) { if (!err) { norf(quxResult, function(err, norfResult) { if (!err) { console.log("Great Success!"); } else { console.error("Could not norf"); } }) } else console.error("Could not qux"); }); } else console.error("Could not baz"); }); } else console.error("Could not bar"); }); } else console.error("Could not foo"); });
50. Async Waterfall (not at all related to the development methodology)
51. async.waterfall([ function(cb) { foo(42, cb); }, bar, baz, qux, norf ], function(err, result) { if (!err) { console.log("Great Success!"); } else { console.error("Could not norf: " + err.message); } });
52. Better, but not perfect
53. A Promising Solution
54. foo(42) .then(bar) .then(baz) .then(qux) .then(norf) .then(function(norfResult) { console.log("Great Success!"); }) .catch(function(error) { console.error("Could not norf: " + err.message); });
55. Promises are like monads
56. User.find(42).then(function(user) { // returning a promise return user.getPosts(); }).then(function(posts) { // posts is the resolved value });
57. User.find(42).then(function(user) { // returning a value return user.name; }).then(function(name) { // name === user.name });
58. Functional.
59. User.find(42).then(function(user) { return user.getPosts(); }).filter(function(post) { return /Lorem Ipsum/.test(post.body); }).map(function(post) { return post.getComments(); }).reduce(function(total, comment) { return comment.getLikes() .then(function(likes) { return total + likes.length; }); }, 0);
60. Broken Promises...
61. User.find(42).then(function(user) { return user.getPosts(); }).then(function(posts) { // yay, I have posts! // but where is my user? }).then(...); Bringing ‘user’ to the party
62. User.find(42).then(function(user) { return user.getPosts() .then(function(posts) { // yay, I have posts! // and I have a user! )}; }).then(...); Promise Hell?
63. var user; User.find(42).then(function(_user_) { user = _user_; return user.getPosts() }).then(function(posts) { // yay, I have posts! // and I have a user! }).then(...); Klutzy variables?
64. var findUser = User.find(42); findUser.then(function(user) { return user.getPosts(); }).then(function(posts) { var user = findUser.value(); // yay, I have posts! // and I have a user! }).then(...); ‘Resolved’ values?
65. var nizzleUserPosts = function(user) { return user.getPosts() .then(function(posts) { // yay, I have posts! // and I have a user! }); } User.find(42).then(nizzleUserPosts) .then(...); Refactor that Shizz-Nizzle!
66. Regret?
68. Non-blocking means code sometimes runs off without you
69. The WTFs of Asynchronous-ness “I called this here and it console.log’s there, wtf?” “Foo is happening before Bar, wtf?” “I called Bar, but it never happened, wtf?” “I never called Baz, but it’s happening, wtf?”
70. I’ve never missed ActiveRecord so much
71. Sequelize ORM
72. Migrations that needed to be migrated
73. Table “SequelizeMeta” has no column “to”
74. Associations that can’t associate
75. User.hasMany(Post); //... User.find(42, {include: Post}); //... Error: User and Post not associated!
76. Source Maps while testing, anyone?
77. $ gulp test ... TypeError: evaluating ‘z[fn]’ /MyBlog/models/user.coffee:1:1 ... /MyBlog/models/user.coffee 1: ‘use strict’ 2: 3: module.exports = 4: foo: ->
78. This is not the require you’re looking for
79. Ruby: FooBar = require ‘foobar’ # Now you have FooBar module # ... everywhere!
80. Node.js: FooBar = require(‘foobar’); // Now you have FooBar module // ... in this file only
81. Circular dependency nightmares
82. require(‘foo’) in ‘bar’ require(‘bar’) in ‘foo’ you’re gonna have a bad time
83. Sometimes I wish I could just `rails c`
84. Sometimes I wish I could just `binding.pry`
85. Acceptence
86. Express.js is fantastic
87. app.use(function(req, res, next) { // write some middlewarez next(); });
88. MIDDLEWARE ALL THE THINGS!
89. Authentication?
90. DB Connection?
91. Asset Pipeline?
92. `before` hook?
93. Middleware!
94. Node.js has come a long way
95. This ain’t yo mamma’s JavaScript
96. Walmart, PayPal, Ebay, Linkedin can’t be wrong, right?
97. Praised for its short development time
98. And IO performance (thanks to non-blocking)
99. ORMs and RDBMS support not quite there yet (IMO, don’t quote me)
100. But huge NoSQL support (mongo, couch, etc)
101. Large, complex, enterprise-y software? maybe not
102. Microservices? Absolutely!
103. Thanks