Thinking in React
React is, in our opinion, the premier way to build big, fast Web apps with JavaScript. It has scaled very well for us at Facebook and Instagram.
One of the many great parts of React is how it makes you think about apps as you build them. In this document, we’ll walk you through the thought process of building a searchable product data table using React.
Step 1: Break The UI Into A Component Hierarchy
The first thing you’ll want to do is to draw boxes around every component (and subcomponent) in the mock and give them all names. If you’re working with a designer, they may have already done this, so go talk to them! Their Photoshop layer names may end up being the names of your React components!
Step 2: Build A Static Version in React
Now that you have your component hierarchy, it’s time to implement your app. The easiest way is to build a version that takes your data model and renders the UI but has no interactivity. It’s best to decouple these processes because building a static version requires a lot of typing and no thinking, and adding interactivity requires a lot of thinking and not a lot of typing. We’ll see why.
Step 3: Identify The Minimal (but complete) Representation Of UI State
To make your UI interactive, you need to be able to trigger changes to your underlying data model. React achieves this with state.
To build your app correctly, you first need to think of the minimal set of mutable state that your app needs. The key here is DRY: Don’t Repeat Yourself. Figure out the absolute minimal representation of the state your application needs and compute everything else you need on-demand. For example, if you’re building a TODO list, keep an array of the TODO items around; don’t keep a separate state variable for the count. Instead, when you want to render the TODO count, take the length of the TODO items array.
Think of all the pieces of data in our example application. We have:
- The original list of products
- The search text the user has entered
- The value of the checkbox
- The filtered list of products
Higher-Order Functions
Tzu-li and Tzu-ssu were boasting about the size of their latest programs. ‘Two-hundred thousand lines,’ said Tzu-li, ‘not counting comments!’ Tzu-ssu responded, ‘Pssh, mine is almost a million lines already.’ Master Yuan-Ma said, ‘My best program has five hundred lines.’ Hearing this, Tzu-li and Tzu-ssu were enlightened.
Master Yuan-Ma, The Book of Programming There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies.
C.A.R. Hoare, 1980 ACM Turing Award Lecture
