I was hoping this would be a guide on managing architectures, common use case traps for handling things like scalability and state. Instead this is just a long-winded way of recommending an opinionated front-end tech stack with resources to learn those stacks. Was not exactly what I was hoping for.
Yep, this is just rehashing the same stuff you can find on any one of 1000 other blog posts, articles or pieces of documentation.
The current literature on front-end development in React is woefully short on real world case studies. It seems like everyone is building 30k loc throwaways with a 40 library boilerplate and slathering the internet with masturbatory praise for all the tooling and architectural patterns involved. If you try and Google for any actual details about said libraries, it's buried under mounds of beginner tutorials and faux praise.
For example, we just made the decision to use ImmutableJS in a project. Everyone else on the team seems to be happy enough just reading a few blog posts about how great it is and then throwing it into the mix. I have a bunch of questions though, where are all the benchmarks? The docs, and everyone else, claims massive speedups from using immutable data structures, but it's never accompanied by any actual metrics, at least as far as my Google-fu gets me. All of our data lists are paginated server side, we're not doing any mass inserts on large data structures anywhere, and I've never noticed a performance problem on anything else I've written with similar requirements, so I find the claim that ImmutableJS is somehow going to speed up our app to be dubious at best. Moreover, every article under the sun craps on about how great it is to "enforce immutability", but nobody seems to be able to tell me when they last encountered a bug due to an inadvertant mutable update, how much time it cost them, or why they're hiring people who make such elementary mistakes in the first place; or if they do, it's some airy parable with no code example of the bug or the ImmutableJS code that could have fixed it.
You don't need a library. Just have a policy that everything should be immutable by default and only turn into mutable objects when optimizing, for example for-loops. The benefit with immutability is not performance (it's actually slower) but manageability and debug-ability. It's easier to reason about code when the variables doesn't change, and you'll get all the variable-states when debugging.
Example:
The "Performance" section of Facebook's own React docs has this line at the end:
"Immutable data structures provide you with a cheap way to track changes on objects, which is all we need to implement shouldComponentUpdate. This can often provide you with a nice performance boost."
What I don't really get is, if you've implemented PureComponent and shouldComponentUpdate wherever possible, how can adding Immutable possibly improve performance? I.e. if your components are ASSUMING their inputs are immutable, how does throwing errors on mutation attempts actually speed things up?
What I don't really get is, if you've implemented PureComponent and shouldComponentUpdate wherever possible, how can adding Immutable possibly improve performance?
The argument is that if you prevent mutation then you can rely on only a shallow comparison of the object references as a reliable test for whether any of the data has changed. Your shouldComponentUpdate implementation becomes a one-line equality test for each prop that might change, or the equivalent. This may be significantly faster (and potentially easier to maintain) than any more detailed comparison of props to decide whether anything significant has changed in shouldComponentUpdate.
Of course, this doesn't address the performance implications of maintaining your state in some sort of immutable data structures rather than just mutating it. Nor does it address the performance implications of using a library like React that declaratively renders your content and does the whole vDOM diff algorithm thing instead of just poking the DOM in exactly the required places. Both of those strategies can be orders of magnitude slower than the alternatives, and both of them can cause architectural and maintenance headaches of their own, and so the questions in those cases are whether the performance is still good enough and whether the benefits in other respects outweigh those costs.
With immutable objects, you can compare them (obj1 === obj2) and assume that if they're the same, none of the properties have changed. You don't have that sort of guarantee with normal JavaScript objects, so you need to do a deep comparison.
If your component's state and props are immutable objects, then shouldComponentUpdate becomes a much easier problem to solve.
The standard, non-library way of handling state in React is to use plain old mutable Javascript objects, and just pretend they're immutable (i.e never perform any mutable operations on them). The popular claim is that Immutable "enforces" immutability, leading to less "accidental mutation" bugs. (A claim which is bogus IMO. 0 !< 0)
No, I'd say it's a _fairly_ valid claim. You have to interact with Immutable.js objects using its API, and every update API call returns a new instance. So, it _does_ generally enforce immutability. As far as I know, the only way to accidentally mutate stuff with Immutable.js is if you insert plain JS objects inside an Immutable.js object, and possibly also use one of its "update this using a callback function" methods and misuse things inside the callback.
Yeah, adding Immutable.js will not magically give you a speed boost.
Immutable.js gives you three primary benefits:
- Its object API largely prevents accidental mutations (although I think it's still possible to make mistakes if you use some of the updater callback methods)
- Internally, it uses specialized data structures that allow "structural sharing" of values. That means that creating a new object based on an existing one doesn't have to copy every single key/value pair onto the new object. This does show perf improvements for copying very large objects (thousands or tens of thousands of keys).
- React perf optimization generally relies on implementing `shouldComponentUpdate` to skip unneeded re-rendering. The standard approach to implementing `sCU` is a shallow equality check that relies on you having handled your data immutably so it can just compare references. React's built-in PureComponent class also implements that approach. As mentioned in other comments, you don't _have_ to use Immutable.js to handle data immutably, but it is one way to do it.
My links list does have links to several discussions of Immutable.js perf [0], and there's specifically one excellent article I've seen that does benchmarks of Immutable.js usage [1] [2]. I also wrote a Reddit comment a while back discussing the reasons why I generally advise against using Immutable.js [3].
As for your comments and questions about app architecture... based on your app description, I don't think Immutable.js would provide any particular speed benefit for you in terms of copying/updating objects. "Enforced immutability", though, _is_ key if you're using Redux, as it's a prerequisite for proper time travel debugging and correct React-Redux UI updates (per my blog post "The Tao of Redux, Part 1 - Implementation and Intent" [4]).
Other than that, my links list does have pointers to many articles about practical usage and lessons learned from real-world React and Redux applications [5] [6].
Your complaints are a bit on the general side, but as always, I'm happy to try to answer any specific questions you might have regarding React and Redux usage.
Anyone know of a good article/series dealing with this? Tooling is fine and well, but I just got bumped to a lead role, with no one more experienced than me around, and could desperately use some more guidance.
This guide is more for beginners who just joined or want to join big tech companies. But I can see that your suggestions would make a great "power up as beginners" guide.
Maybe I'm confused, but I always thought front-end development included graphics design. It seems like this guide does not discuss graphics design at all. I don't just mean Photoshop, but also subjects like when/where to use which color, typography, etc. Also this guide contains no information about other product design disciplines such as requirements gathering etc.
I was working for a Dutch company a few years ago and our front-end developers worked closely with the graphics designers and the back-end developers to be able to properly do their work. We also had a business analyst who was working more on requirements gathering. In the end the entire team was however responsible for creating a good product for the customer.
I've seen the front end devs you describe in (some) smaller Aussie companies. OTOH every front-end dev I meet in San Francisco does HTML + CSS + JS. In a large enough place, they don't even need the CSS, some other team maintains that and publishes the internal equivalent of http://getbootstrap.com/components/
It makes sense to me that you specialize once you get past a certain team size on the same product.
"Front end development" didn't exist as a separate software development discipline until a few years ago. Before that, you had "web developers" for a while, and before that, "web designers". These latter two categories were people whose primary responsibility was to translate Photoshop designs into HTML and CSS, and for that they needed, at least, a strong eye for visual design. Their use of JavaScript was limited to use of libraries like Scriptalicious, Mootools and (later) jQuery to add "Web 2.0" enhancements. Oftentimes they were simply designers who'd learnt HTML and CSS in order to help accurately translate their own designs, either because there was nobody else to do it, or because they couldn't entrust it to back-end programmers.
Although the roles of designer and front-end developer were gradually bifurcating by around 2010, if you were recruited by an agency as a front-end developer, you were still almost certainly expected to demonstrate graphics design abilities, and would often be considered part of the design team than the programming team. It was only really with the rise of Single Page Applications that you started to see front-end development completely shed its origins as a adjunct to a designer's role.
The picture was never quite as black and white as you're suggesting, I think, though certainly there were plenty of the kind of people you mentioned around. For example, some people working in web world have always just built stuff directly in-browser rather than slicing Photoshop images. This wasn't a new idea when responsive sites came along, nor when SPAs started to become a serious business; those trends just provided more awareness to some people who hadn't thought of working that way before. Some people expanded from a programming background into making more interactive web sites rather than from a design background, and it probably would never have occurred to them not to at least consider building with the native technologies from day one.
It's true that as those front-end technologies develop, more substantial programming work is being done on the browser side, and so there has been a degree of specialisation in the roles involved, particularly in larger organisations. Even so, I'm not personally a fan of trying to maintain too strict a division between those roles. As with almost anything in a technical field, if you don't have at least a basic working knowledge of related skills and technologies, you're probably not going to be very good at whatever specialist task you're trying to do either. Similarly, if some key decisions and resources aren't managed by all of the relevant people collectively, problems will inevitably creep in for those who weren't as involved as they should have been.
I guess in the company I was working for we valued employees with T-shaped skills (https://en.wikipedia.org/wiki/T-shaped_skills), in which people have one discipline in which they are experts (such as HTML/CSS/JS and the supporting infrastructure) and they have enough experience with the related disciplines (i.e. graphics design, requirements engineering, back-end development) to collaborate with experts in that field.
While that naming sounds a bit too MBA-ish for my ears, it does a good job capturing a concept that I have been trying to pin down for a while now in terms of the types of job candidates that have worked out best for me. Thank you for the metaphor, and for what it's worth, I agree in it being a desirable skill distribution.
Incidentally, people at our company who have acquired said combination of wide skill breadth with a specific skill depth, got there because one employer or another (not always us) hired them when they were intent on (or already in the process of) a change of role. For instance, someone with a few years in graphics design who, when given a chance to (or being required to) work with HTML and CSS, found that not only did they like it, they wanted to learn and do more, even if that meant transitioning
There are all sorts of questions I have about how that might fit into the arc of someone's career, how it affects salaries, and so on. Furthermore, I do not think it should be the only lens by which to assess people's skills, at the exclusion of all else. It just seems that many of our A-Players, as it were, came into our organization with that sort of skill distribution, or quickly grew to have it.
Yes, I always try to remember this quote, "Front End is the melting pot of design & development skills to implement accessible interfaces to accepted standards."
It's an excellent set of advice and resources. Good explanations of why each topic matters and what it includes, with links to a few selected resources for each topic and an estimate for study time. I've already added it to my standard advice for getting started with React.
I'm _very_ pleased to note that the guide links to my "(R)Evolution of Web Development" presentation [0] and my React/Redux links list [1], and that a number of the other articles referenced are definitely based on my links list contents too :) (Also, for good measure, I'll toss in a link to my "Intro to React and Redux" presentation here as well [2].)
It's a great guide with excellent suggestions along the way. I would suggest adding few links on React Optimization to it. A guide on how to break React components and how to implement store/state once you start to scale would be very helpful. :)
This guide is meant as an overview of an array of technologies. My React/Redux links list, on the other hand, has you covered :) See the "React Performance", "React Architecture", "React Component Patterns", and "Redux Architecture" sections:
Your list has been absolutely instrumental in my path towards mastering react/redux. A big thank you for all the hard work. You are multiplying the communities knowledge and we're all improving because of it.
Grab is the Southeast Asia rival to Uber. Their stronghold is in Singapore, but they're the market leader in that region. Alibaba is looking to invest in their $1.4 billion upcoming round led by Softbank. I know for a fact that they are creating a technical, iOS development center of excellence in Seattle ...
I've always disliked these top down plans that require so much setup and upfront work. The best tools I've worked with are progressive in their discovery and mastery of features without lowering the ceiling too much. Sublime for example has a command palette to just fuzzy type your desired command as a fallback, showing the shortcut key right next to the command as well. Vue also markets itself as having this type of "progressiveness".
Reminds me of vim fans. There's always an undercurrent of elitism or hazing where something "hard" must be done to be "worthy" of some sort of goodness.
"At Grab, we use ES2015 (with Babel Stage-0 preset) to enjoy the productivity boost from the syntactic improvements the future of JavaScript provides and we have been loving it so far."
You've not been using it that long then! Stay alive and stick with Stage-3
Well, async/await and several other features were held up at stage1/2 for a long while. I found quite a few things very valuable far earlier on... async/await, object rest/spread, class (static) property syntax.
Now most of it is stage-3 or in-browser, so not a bad decision, but for a long time, you really wanted to be at stage-0/1 and deal with a bit of pain should things change.
Async/await was the pitfall for one project as they weren't just held up but they changed API during experimental implementations. Less concerning now you can write codemods to transform but if you don't own the code it's better to keep your client a little behind and safer.
For large apps and teams, I would recommend CxJS. CxJS is based on React and offers a more streamlined development experience with a built-in library of widgets and charts, themes (including Material), and other features such as form validation, form layouts, culture-sensitive number and date formatting, optional two-way data binding and much more.
Full disclaimer: It's a commercial product and I'm the lead developer.
The wide adoption of Flow and TypeScript means that people are starting to realize that explicitly typed code is easier to maintain than implicitly typed code.
Hopefully a new EcmaScript version adds the ability to specify types. It's either that or people opting out of JS in favor of wasm based tech in the near future.
I think it largely falls to the size and discipline of the teams doing the work. I get by pretty well without them, but if I had to coordinate with over 20 other developers working in a single codebase, then I'd have a differing opinion. I'd also be pushing for 100% test coverage as it's FAR easier to do in JS than it is in other languages. Of course, adding types makes it harder again.
I used to share this opinion as well, until I started working on an internal library that was created by a skilled developer. He had very good test coverage and good quality tests, which turned out invaluable, once I got on board. We tried to move to library towards being fully typed in TypeScript, just to get some experience with TypeScript. Our first thought before starting was, that it would help, but didn't expect it to have a significant impact. During the port to TypeScript (and being strict on typing everything possible), we soon found numerous unexpected behaviors in the code. Some of the issues found, could have been found by a linter, but other things like models changing over time was only found due to adding static types.
After this experience I changed my opinion towards the value of static types, from being more than a nice to have feature.
This was a disappointing read, coming from such a large company, looking like a disposable blog post.
It makes it sound like front end development is about knowing CSS, react and redux, these are good options of tools for the job, not essential ones, especially when Vue and Angular are still big in the scene.
Maybe I'm wrong about my own profession, as some other comments said, it is often blurry and in the past it used to be more related to graphics design even, but for me front end development is about programming, just as full stack but without worrying about business logic that is supposed to rely on the backend. This can include design(as in CSS, colors, grids, fonts, responsiveness), but also worrying about the delivery mechanisms(some API level knowledge, browser vendors), including performance(consider crappy or inconsistent networks).
There's nothing in this guide that couldn't be found on 1000s of other introductory blog posts. This is just "What to Use With React 2017". I find it almost disturbing that front-end jobs around the world have adopted a set of opinionated tools that are so needlessly complex and churn at an amazing rate, and devs themselves have such a cavalier attitude about it. The self-congratulatory praise is deafening.
I'm surprised that Flow is recommended over Typescript. Flow's main strength seems to be the ability to slowly integrate it into a large existing project. Since this guide seems to be targeted at new applications I don't see why Typescript wouldn't be the better choice.
Funny, if you just suggested EmberJS you could cut out a large portion of this guide. Good guide nonetheless for those looking to hack together their own front-end stack.
