Brandon Konkle
Brandon Konkle

Principal Engineer, type system nerd, Rust enthusiast, supporter of social justice, loving husband & father, avid comic & manga reader, 日本語を勉強してる。

I’m a Software Architect with more than 15 years of experience creating high performance server and front-end applications targeting web and mobile platforms, & today I lead a team at Formidable Labs.



Brandon Konkle

Why React?

React is an outstanding compromise between pure, functional, declarative principals and the loose, dynamic reality we work within.

React is an outstanding compromise between pure, functional, declarative  principals and the loose, dynamic reality we work within. It allows  developers to write interfaces in a component-driven way that describes  the result of a render based on the current properties and state at the  moment. Behind the scenes, it uses an efficient diffing algorithm to  keep your UI up to date using the minimum number of manipulations  possible.

Components let you split the UI into independent, reusable pieces, and think about each piece in isolation.
React - Components and Props

With React, you can gradually transition your application from prototype  to production, adding strictness as you're ready for it with tools like  TypeScript and unit testing. You can use it as a universal pattern for  crafting interfaces across diverse platforms, while maintaining a sound  functional core that is shared between each application. Like any  powerful tool, though, it's easy to misuse. With some planning and  discipline, however, you can achieve a high level of stability while  still keeping your code maintainable for those who come behind you.

A Brief History

On May 29, 2013, Facebook released the initial open source version of  React. It was created by Jordan Walke and inspired by Facebook's XHP  project, which was itself inspired by another project called E4X. These  libraries both allowed you to easily embed XML in other languages, which  led to the creation of JSX—an extension of JavaScript syntax that  allows easy embedding of XML/HTML.

This may be the single most controversial aspect of React. Writing HTML  in the middle of your JavaScript files initially felt like a return to  the jumbled days of inline PHP. I was personally very critical of React  for it in the beginning. Today, however, I hold JSX in very high regard  as a great way to dynamically express composable elements of a user  interface so that they are easy to visually scan and understand. It's  what makes React's elements on the web and in native platforms so easy  to take in at a glance.

Some time after Instagram joined the Facebook family, Pete Hunt was  introduced to React and wanted to use it for Instagram. He worked with  others at Facebook to refactor it into an open source package to give  back to the community. It was initially received with some confusion and  skepticism. In addition to protests about separation of concerns in  JSX, there were also loud critics comparing React to Angular and Ember  and pointing out the lack of two-way binding, and criticizing Facebook's  unorthodox "virtual DOM" approach to managing DOM updates.

The virtual DOM is a programming concept where an ideal, or “virtual”, representation of a UI is kept in memory and synced with the “real” DOM. [...] This abstracts out the attribute manipulation, event handling, and manual DOM updating.
React - Virtual DOM and Internals

Facebook's Bill Fisher stepped in to clarify their approach to one-way  data flow by open sourcing Flux, an architectural pattern for reactive  interfaces built around what was essentially an event loop. Stores  formed the single source of truth for the interface, and DOM events  ended up dispatching actions to the stores to update them. When stores  were updated, React components were re-rendered based on the new state.  In typical front-end MVC frameworks of the day this approach would be  far too inefficient to be viable. The virtual DOM makes this possible by  automatically managing DOM manipulation and only updating elements when  they change.

Despite the prominence that the virtual DOM enjoys today, the team's  initial focus was on JSX and reusable components. The virtual DOM was a  way to make it perform well enough to be practical. The result is an  efficient system for managing rendering in a predictable and  maintainable way.

Managing Mischief

That's all well and good, but when it comes down to it why would you  choose React rather than one of the infinite alternatives out there on npm?  The bottom line is that the front end - regardless of whether that  front end is an HTML/CSS/JS document rendered in a web browser or a  native mobile view rendered in the React Native runtime - is a chaotic  asynchronous event-based system that runs in tightly constrained  execution environments. It is often error-prone and difficult to debug.

React introduces a declarative, functional interface  that makes it easier to manage rendering in a maintainable way. To  achieve this, it uses a diffing algorithm against an in-memory  intermediate representation of your interface to make the minimal set of  UI changes necessary for each render. This cuts down on the work that  the browser or React Native runtime needs to do to keep your UI up to  date as things change.

A declarative language abstracts away procedural details, instead focusing on the form of the result.
Composing Programs 4.3 - Declarative Programming

Though the ability to combine HTML, CSS, and JavaScript all in one file  initially seems contrary to traditional best practices - it enables  rich, expressive interfaces that are automatically bundled into the  traditionally separated layers for efficient usage by the browser.

With these tools, you're able to build encapsulated components  that make it easy to reuse logic and write comprehensive unit tests  around what matters. You can organize your interface into single units  of functionality and/or style, composing them together into rich  interfaces formed from reusable building blocks.

Encapsulation refers to the idea that objects should manage their own behavior and state, so that their collaborators need not concern themselves with the object’s inner workings.
Deviq - Encapsulation

The ability to render not just to DOM and the browser, but to render to  other platforms like native iOS and Android views is a very powerful  abstraction that allows you to use the multitude of tools available on  npm to build easily maintainable mobile applications without having to  know a large amount of platform-specific code.

The ability to share a core set of logic across those platforms is the  killer feature that makes React the absolute best way, in my opinion, to  write cross-platform applications in a fraction of the time that it  would normally take.

Gradually Functional

React enables functional programming patterns in a way that can be  applied gradually, enforcing strictness and purity where needed and  allowing looser implementations for prototyping or pre-release code. It  doesn't enforce purity or prevent an object-oriented approach, but it  gives you a great set of tools to describe your interface purely given  the current state at any point in time and keep it up to date  efficiently.

To take full advantage of this, however, it's necessary to use React  with restraint and discipline. As with much of the JavaScript ecosystem,  you get plenty of ammunition to shoot yourself in the foot with. To  prevent unpredictable errors but still keep your code easy to maintain  over time, a good strategy is to keep a strict, functional core of  business logic and API interactions, wrapped in a dynamic shell of  presentation and markup.

If your state management and actions, API clients, and core logic are  kept as strict and functionally pure as is practical, then it's  relatively easy to wrap and re-wrap them in presentational views for  different contexts or even different device platforms.

Functional Core, Imperative Shell (diagram by Nat Pryce in Growing Object-Oriented Software)

React's flexible nature also allows for quick iteration and prototyping  at first, while gradually embracing more sound code as you approach  production. In well-crafted design systems built with React, designers  can often come in and use a set of composable React building blocks to  mockup interfaces in real code with no need to dip into the HTML or CSS.

Though I love purity and sound functional programming, I've found the  flexibility of React to be ideal for building real-world interfaces in a  practical and iterative way. Combined with tools like TypeScript,  especially, it can still provide a platform for tight correctness while  still being usable in a tight-deadline environment. ⚛︎

I’m a Software Architect with more than 15 years of experience creating high performance server and front-end applications targeting web and mobile platforms, & today I lead a team at Formidable Labs.

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