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React best practices and patterns to reduce code - Part 2

Rahul Sharma on March 18, 2022

I've another article about React best practices and patterns to reduce code. It's a good article to read before you start to write your own React c...

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Eric B • Mar 21 '22

Use object state if you have to update multiple states together

Not really, no. Use useReducer.

Use styled-components

No.

Use object(Map) instead of switch statement

... while there are places where this does make sense, especially if you're in a component that is otherwise 100% declarative, for the most part, avoid.

Use object destructuring instead of passing multiple props by name to a component

Absolutely not. Always pass exactly the parameters you need. Do not ever pass a wholesale ...rest props to a component.

Use fragment

Wow! OK, I was not aware of Fragment. Great tip . . . when it's useful. It has a specific purpose, and your example is not it.

ianhfar • Mar 24 '22

"Use styled-components to style your components."
This should be highlighted as your opinion.
Not sure you can argue this is a must.

By separating your styling into a css file, you are not polluting your source with styling.

Rahul Sharma • Mar 24 '22

Thanks for suggestions, I've added.

Cédric Teyton • Feb 16 '23

Hello Rahul, FYI we've added your blog post on a GitHub project gathering content about best coding practices :)
github.com/promyze/best-coding-pra...

stunaz • Mar 19 '22 • Edited

About the last exemple on the key : why not use the key in SomeComponent even if you dont use the key. i.e. like :

return (
  <>
    {list.map((item) => (
        <SomeComponent  key={item.id}/>
    ))}
  </>
);

Rahul Sharma • Mar 19 '22

Thanks for pointing it out, I've missed one more component. I meant was this

return (
  <>
    {list.map((item) => (
      <React.Fragment key={item.id}>
        <SomeComponent />
        <SomeComponent />
      </React.Fragment>
    ))}
  </>
);

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eBitzu • Mar 19 '22

Please delete sections of your article you don't know how they really work. The worst thing you can do is to teach people bad stuff

Multiple setState are now batched.
Functions outside of jsx but inside component are basically the same thing, new function on every render
Props destructoring is considered bad practice
React.Fragment suports key

John Soriano • Mar 20 '22 • Edited

All your complaints are addressed in this post.

He said multiple states can be batched. there are notes. are you read the post?
Isn't re-render or re-evaluate the function because it wraps in useCallback, you just have pass to deps in order not to re-evaluate. please educate.
Who said destructuring is bad practice? it's one of Javascript edge, as long as you know the props being passed.
React.Fragment he said that, are you reading the post?

Rahul Sharma • Mar 20 '22

@johnsoriano Has already answered few of questions.

React batching is not available in the current react version. It'll be available for react-18, react-18 is rc releasead.

eBitzu • Mar 20 '22 • Edited

Stop saying I don't read the article, as the article was updated after my comments. Use you brain...

Batching is available in 17, but not for async situations like setTimeout

Rahul Sharma • Mar 20 '22 • Edited

I agreed, but that's why I added setTimeout in my example. I've not updated article example, I just added note of react 18.

Max Saperstone • Mar 20 '22

This is a great article. One thing I've done in the past is setup ESLint to catch some things like this. I'll look to see if I can add some more, but it'll auto catch and even fix a lot of these things

Anish De • Mar 20 '22

This is quite an useful article!

I have 1 question, what is wrong with using props like className for component props? Maybe I have a Button component that has some pre-defined styles but I will also keep the option to add more styles later on (say margins or text size) using the className prop whenever I re-use the component. Will it be not a better way than declaring variants for every possible situation?

Rahul Sharma • Mar 20 '22 • Edited

You can use there is no hard and fast rule, But try to avoid for any custom prop. let say you have button component you want 2 types of button contained and ghost, so don't use like style="ghost" or style="contained".

const type = "ghost" === props.style ? "something" : "something"

Anish De • Mar 20 '22

Ah, I see.

dommirr • Mar 19 '22

it's good to know React.memo to avoid unnecessary renders. But I think it is more important to know how to make good use of React.memo since we tend to misuse it.

Rahul Sharma • Mar 20 '22

Good point, I'll add note for that. Thank you for pointing it out 😊

Gabriel Linassi • Mar 24 '22 • Edited

I'd add some more:

Composition
Extract useEffect logic into a custom hook
Try to use useRef instead of useState for inputs
Don't put into state info you can get from reading other states

Examples:

<Layout>
   <Layout.SidePanel>{ ... }</Layout.SidePanel>
   <Layout.Main>{ ... }</Layout.Main>
</Layout>

const { cart, loading, error } = useCart()
...
return cart.items.map(item => (...))

Mansour Koura • Mar 24 '22

HEY MAN! YOU ARE AWESOME!

Use object(Map) instead of switch statement. I've already mentioned the same in my previous article for reducers.
Use styled-components to style your components. This is a good way to avoid writing CSS in JSX and also helps to avoid CSS setup for the application.
Use object state if you have to update multiple states together.
Don't write functions inside JSX elements.

All of those ones Realy amazing! and I will start using them immediately, please write more!

Peter Kelvin Torver • Mar 20 '22

"Use React.memo() wisely, don't use memo where component often re-renders with props."
Can u explain why? Supposing I have a child component that takes props, what you suggest I should? Don't call React.memo() on the child component?

Rahul Sharma • Mar 22 '22

don't use memo where component often re-renders because of props. React.memo does not help because it's anyway going re-render.

Mario Lemus • Mar 19 '22

Pretty good content, ¡thanks!

vzpintor • Mar 20 '22

Can you share me the article
Use object(Map) instead of switch statement. I've already mentioned the same in my previous article for reducers.

I don't have clearly why es better use man instead of switch

Rahul Sharma • Mar 20 '22

dev.to/devsmitra/react-best-practi...

Point number 2, It's almost similar to redux-toolkit.

Comment deleted

Rahul Sharma • Mar 20 '22 • Edited

Thanks Alexandr, But in this article I've not used any difficult words. Only heading that can converted into another language, I believe that much also all software engineers/students can understand.

Comment deleted

Rahul Sharma • Mar 20 '22 • Edited

My point is heading can understand by anyone, it does not require expertise in english. Code anyway not going to change.

Alexandr • Mar 20 '22

Okay, thanks btw

Rahul Sharma • Mar 23 '22 • Edited

@doberman2029 You can translate, but make sure you add the original blog link also.

sharan • Mar 22 '22

const onClick = useCallback(() => {
setCount(1);
// ...
}, [deps]);

return (

Click

);

Why are we using usecallback here. is there any specific reason here.

Mark Butterworth • Mar 26 '22

If setCount was the only thing called then it would be pointless but all these hooks are just different forms of memoization used for different purposes.

useCallback creates a cached method preventing a re-render if the deps did not change. useState dispatcher already does this so memoizing it alone adds no value.

Dmytro Dmytro • Jun 11 '23

Useful! Thanks! I would recommend to read this one: webman.pro/blog/react-best-practices/

Johan Ezequiel S. Linares • Mar 20 '22

For the last example of the keys, could Children.ToArray be used?

Rahul Sharma • Mar 20 '22

Actually, my intention was to show if we have 2 components, that could be the same or different. I think my example is creating confusion, I've updated the example hope that helps.

Santi López Bayo • Mar 25 '22

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