Real World Lessons On The Anti-Patterns of Node.JS
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The document details the author's personal experiences and challenges with Node.js, focusing on anti-patterns related to modules, npm, project structure, asynchronous programming, and error handling. The author emphasizes the importance of locking down dependencies to prevent build issues and suggests best practices for structuring code and handling errors effectively. Despite these challenges, the author acknowledges the powerful capabilities of Node.js when used correctly.
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Real World Lessons On The Anti-Patterns of Node.JS
- 1. REAL WORLD LESSONS ON THE ANTI -PATTERNS OF NODE.JS @Ben_Hal l Ben@BenHal l .me.uk Blog.BenHal l .me.uk
- 2. MY BATTLE SCARS OF NODE.JS @Ben_Hal l Ben@BenHal l .me.uk Blog.BenHal l .me.uk
- 3. MY LIFE, MY STORY, MY ANTI -PATTERNS BY BEN HALL. PUBLISHER TBC
- 4. $ whoami Tea boy > Tester > Developer > Freelancer > Tea boy? Ocelot Uproar
- 5. My main pain points & agenda • Modules + NPM • Project St ructure • Async • Er ror Handl ing
- 6. Disclaimer Examples are not a ref lect ion on the developer / team/company. Based on problems I ’ v e c a u s e d mysel f or st ruggled wi th. JavaScr ipt is very subject ive…b l a h b l a h b l a h… I f y o u ’ r e d o i n g i t r i g h t t h e n *amazing* ! I ’ m n o t . Love, Ben x
- 10. AngularJs 1.2 => 1.3 1. "dependencies" : { 2. " a n g u l a r " : " ^ 1 . 2 . 1 6 ” 3. }
- 11. Angular 1.2 => 1.3 > angular.element (document ) [#document ] > angular.element (document ) TypeEr ror : undef ined is not a funct ion
- 12. Lock Down Dependencies Randomly breaking bui lds and deployments wi l l occur otherwise
- 13. $ npm shrinkwrap Lock down dependencies to w h a t ’ s r u n n i n g l o c a l l y
- 15. Hard code versions in package. json 1. "dependencies" : { 2. " a n g u l a r " : “ 1 . 2 . 2 3 ” 3. }
- 16. $ npm outdated
- 17. $ npm install Downloading the internet on each deployment can be slow
- 18. $ npm install --production
- 19. “HELPERS” & PROJECT STRUCTURE
- 20.
- 21.
- 22.
- 23. Libs/<Context>/<Task>.js Why not an NPM?
- 24.
- 25. Be c a u s e J a v aSc r i p t ASYNC
- 26. Promises P r o m i s e s… P r o m i s e s… N e v e r break your promises. Personal ly, never make promises.
- 28. Not part of the Node Makes integrat ion more di f f icul t . Makes swapping code in / out more painful .
- 29. Callbacks S o g o o d i t ’ s g o t i t ’ s o w n websi te cal lbackhel l .com
- 31.
- 32.
- 33. Loops + Async Callbacks
- 34. Loops + Async Callbacks
- 35. Generators are coming! See Node >=0.11.2
- 37. ERROR HANDLING
- 38. Wasn’t great from the start St i l l not great
- 39. Try {} Catch {}
- 40. Try {} Catch {}
- 41.
- 42. Returning String as Error
- 43.
- 44. Zones are coming! See Node >=0.11.2
- 46. Generators + Error Handling
- 47.
- 48. AND FINALLY
- 50. L e t ’s y o u g e t awa y wi t h a l o t wi thout hurt ing too much Modules + NPM Projec t St ruc ture As ync Er ror Handl ing
- 51. @Ben_Hal l Ben@BenHal l .me.uk Blog.BenHal l .me.uk
Editor's Notes
- #9: It’s all about having a good time. If you do blah blah blah you’re going to have a bad time.
- #28: getTweetsFor("domenic") // promise-returning function .then(function (tweets) { var shortUrls = parseTweetsForUrls(tweets); var mostRecentShortUrl = shortUrls[0]; return expandUrlUsingTwitterApi(mostRecentShortUrl); // promise-returning function }) .then(httpGet) // promise-returning function .then( function (responseBody) { console.log("Most recent link text:", responseBody); }, function (error) { console.error("Error with the twitterverse:", error); } );
- #31: var repo_url = $(site).find('li[data-tab="repo"]').find('a').attr('href'); var activity_url = $(site).find('li[data-tab="activity"]').find('a').attr('href'); request.get("http://github.com" + repo_url, function(rr, repo_html) { var $_repo = cheerio.load(repo_html); var repo_list = $_repo('.repolist li'); var results = []; repo_list.each(function(ix, p) { var source = true; if($(p).hasClass('fork')) source = false; var repo = { link: "http://github.com" + $(p).find('.repolist-name a').attr('href'), title: $(p).find('.repolist-name').text().clean(), stars: parseInt($(p).find('.stargazers a').text().clean(), 10), is_source: source, language: $(p).find('.language').text()}; if(repo_list.length === (ix + 1)) { request.get("https://github.com" + activity_url, function(err, activity_html) { var $_activity = cheerio.load(activity_html); var repo_list = $_activity('.alert'); var results = []; repo_list.each(function(ix, p) { var repo = {title: $(p).find('.title').text().clean(), actioned_at: $(p).find('.js-relative-date').attr('datetime')}; results.push(repo); if(repo_list.length === (ix + 1)) { data.repositories = results.repo; data.public_activity = results.activity; callback({parser: 'github', id: data.username, profile: data}); } }); }); } }); });
- #34: var parse_repositories = function(repo_url, callback) { request.get("http://github.com" + repo_url, function(rr, repo_html) { var $_repo = cheerio.load(repo_html); var repo_list = $_repo('.repolist li'); var results = []; repo_list.each(function(ix, p) { var source = true; if($_repo(p).hasClass('fork')) source = false; var repo = { link: "http://github.com" + $_repo(p).find('.repolist-name a').attr('href'), title: $_repo(p).find('.repolist-name').text().clean(), stars: parseInt($_repo(p).find('.stargazers a').text().clean(), 10), is_source: source, language: $_repo(p).find('.language').text()}; if(repo.title !== '') { results.push(repo); } if(repo_list.length === (ix + 1)) { callback(null, results); } }); if(repo_list.length === 0) { callback(null, []); } }); };
- #37: app.post('/users', function *(request) { var user = new User(request.params); if (yield user.save()) { return JSON.stringify(user); } else { return 422; } });
- #42: process.on('uncaughtException', function(err) { // handle the error safely console.log(err); });
- #47: try { var files = yield readdir(dir) } catch (er) { console.error('something happened whilst reading the directory') }