react-philosophies

If react-philosophies helped you in some way, consider buying me a few cups of coffee ☕☕☕. This motivates me to create more React "stuff"! 🙂

You have to think about what is the right way, even when you have the right idea of what the building blocks should be, there is huge flexibility in how you decide to put the whole system together. It is a craft... and it has a lot to do with valuing simplicity over complexity. Many people do have a tendency to make things more complicated than they need to be... The more stuff you throw into a system, the more complicated it gets and the more likely it is not going to work properly. - Barbara Liskov

Translations to other languages

• Chinese by @Leecason
• Korean by @lim-jiwoo

Table of Contents

0. Introduction
1. The Bare Minimum
2. Design for happiness
3. Performance tips
4. Testing principles
5. Insights shared by others

🧘 0. Introduction

react-philosophies is:

• things I think about when I write React code.
• at the back of my mind whenever I review someone else's code or my own
• just guidelines and NOT rigid rules
• a living document and will evolve over time as my experience grows
• mostly techniques which are variations of basic refactoring methods, SOLID principles, and extreme programming ideas... just applied to React specifically 🙂

react-philosophies is inspired by various places I've stumbled upon at different points of my coding journey.

Here are a few of them:

• Sandi Metz
• Kent C Dodds
• Zen of Python (PEP 20), Zen of Go
• trekhleb/state-of-the-art-shitcode, droogans/unmaintainable-code, sapegin/washingcode-book

As a seasoned developer I have certain quirks, opinions, and common patterns that I fall back on. Having to explain to another person why I am approaching a problem in a particular way is really good for helping me break bad habits and challenge my assumptions, or for providing validation for good problem solving skills. - Coraline Ada Ehmke

🧘 1. The Bare Minimum

1.1 Recognize when the computer is smarter than you

1. Statically analyze your code with ESLint. Enable the rule-of-hooks and exhaustive-deps rule to catch React-specific errors.
2. Enable "strict" mode. It's 2022.
3. Be honest about your dependencies. Fix exhaustive-deps warnings / errors on your useMemo's, useCallback's and useEffect's. You can try "The latest ref pattern" to keep your callbacks always up-to-date without unnecessary rerenders.
4. Always add keys whenever you use map to display components.
5. Only call hooks at the top level. Don’t call Hooks inside loops, conditions, or nested functions.
6. Understand the warning "Can't perform state update on unmounted component". facebook/react/pull/22114
7. Prevent the "white screen of death" by adding several error boundaries at different levels of your application. You can also use them to send alerts to an error monitoring service such as Sentry if you want to. (Accounting for Failures In React)
8. There is a reason why errors and warnings are displayed in the console.
9. Remember tree-shaking!
10. Prettier (or an alternative) formats your code for you, giving you consistent formatting every time. You no longer need to think about it!
11. Typescript and frameworks such as NextJS make your life so much easier.
12. I highly recommend Code Climate (or similar) for open-source repositories or if you can afford it. I find that automatically-detected code smells truly motivates me to reduce the technical debts of the application I'm working on!

1.2 Code is just a necessary evil

"The best code is no code at all. Every new line of code you willingly bring into the world is code that has to be debugged, code that has to be read and understood, code that has to be supported." - Jeff Atwood

"One of my most productive days was throwing away 1000 lines of code." - Eric S. Raymond

See also: Write Less Code - Rich Harris, Code is evil - Artem Sapegin

1.2.1 Think first before adding another dependency

Needless to say, the more you add dependencies, the more code you ship to the browser. Ask yourself, are you actually using the features which make a particular library great?

1.2.2 Don't be clever. YAGNI!

"What could happen with my software in the future? Oh yeah, maybe this and that. Let’s implement all these things since we are working on this part anyway. That way it’s future-proof."

You Aren't Gonna Need It! Always implement things when you actually need them, never when you just foresee that you may need them. The less code the better! (Martin Fowler: YAGNI, C2 Wiki: You Arent Gonna Need It!)

Related section: 2.4 Duplication is far cheaper than the wrong abstraction

1.3 Leave it better than you found it

1.3.1 Detect code smells and do something about them if you need to.

If you recognize that something is wrong, fix it right then and there. But if it's not that easy to fix or you don't have time to fix it at that moment, at least add a comment (FIXME or TODO) with a concise explanation of the identified problem. Make sure everybody knows it is broken. It shows others that you care and that they should also do the same when they encounter those kinds of things.

Keep in mind that code smells don't necessarily mean that code should be changed. A code smell just informs you that you might be able to think of a better way to implement the same functionality.

1.3.2 Merciless Refactoring. Simple is better than complex.

Is the CL more complex than it should be? Check this at every level of the CL—are individual lines too complex? Are functions too complex? Are classes too complex? “Too complex” usually means “can’t be understood quickly by code readers.” It can also mean “developers are likely to introduce bugs when they try to call or modify this code.”- Google Engineering Practices: What to look for in a code review

💁‍♀️ TIP: Simplify complex conditionals and exit early if you can.

# ❌ Not-so-good

if (loading) {
  return <LoadingScreen />
} else if (error) {
  return <ErrorScreen />
} else if (data) {
  return <DataScreen />
} else {
  throw new Error('This should be impossible')
}

# ✅ BETTER


if (loading) {
  return <LoadingScreen />
} 

if (error) {
  return <ErrorScreen />
}

if (data) {
  return <DataScreen />
}

throw new Error('This should be impossible')

💁‍♀️ TIP: Prefer chained higher-order functions over loops

If there is no discernable performance difference and if possible, replace traditional loops with chained higher-order functions (map, filter, find, findIndex, some, etc) Stackoverflow: What is the advantage of using a function over loops?

1.4 You can do better

💁‍♀️ TIP: Remember that you may not need to put your state as a dependency because you can pass a callback function instead.

You don't need to put setState (from useState) and dispatch (from useReducer) in your dependency array for hooks like useEffect and useCallback. ESLint will NOT complain because React guarantees their stability.

❌ Not-so-good
const decrement = useCallback(() => setCount(count - 1), [setCount, count])
const decrement = useCallback(() => setCount(count - 1), [count])

✅ BETTER
const decrement = useCallback(() => setCount(count => (count - 1)), [])

💁‍♀️ TIP: If your useMemo or useCallback doesn't have a dependency, you might be using it wrong.

❌ Not-so-good
const MyComponent = () => {
   const functionToCall = useCallback(x: string => `Hello ${x}!`,[])
   const iAmAConstant = useMemo(() => { return {x: 5, y: 2} }, [])
   /* I will use functionToCall and iAmAConstant */
}
       
✅ BETTER 
const I_AM_A_CONSTANT =  { x: 5, y: 2 }
const functionToCall = (x: string) => `Hello ${x}!`
const MyComponent = () => {
   /* I will use functionToCall and I_AM_A_CONSTANT */
}

💁‍♀️ TIP: Wrapping your custom context with a hook creates a better-looking API

Not only does it look better, but you also only have to import one thing instead of two.

// you need to import two things every time 
import { useContext } from "react"
import { SomethingContext } from "some-context-package"

function App() {
  const something = useContext(SomethingContext) // looks okay, but could look better
  // blah
}

  
// on one file you declare this hook
function useSomething() {
  const context = useContext(SomethingContext)
  if (context === undefined) {
    throw new Error('useSomething must be used within a SomethingProvider')
  }
  return context
}
  
// you only need to import one thing each time
import { useSomething } from "some-context-package"

function App() {
  const something = useSomething() // looks better
  // blah
}  

💁‍♀️ TIP: Think about how your component will be used before coding it

Writing APIs is hard. README Driven Development is one useful technique to help design better APIs. I'm not saying we should RDD religiously, just saying that the idea behind it is great. I find that when I first write the API (how the component will be used) before implementing it, this usually creates a better designed component than when I don't.

🧘 2. Design for happiness

"Any fool can write code that a computer can understand. Good programmers write code that humans can understand." - Martin Fowler

"The ratio of time spent reading versus writing is well over 10 to 1. We are constantly reading old code as part of the effort to write new code. So if you want to go fast, if you want to get done quickly, if you want your code to be easy to write, make it easy to read." ― Robert C. Martin (Not saying I agree with his political views)

TL;DR

1. 💖 Avoid state management complexity by removing redundant states
2. 💖 Pass the banana, not the gorilla holding the banana and the entire jungle (prefer passing primitives as props)
3. 💖 Keep your components small and simple - the single responsibility principle!
4. 💖 Duplication is far cheaper than the wrong abstraction (avoid premature / inappropriate generalization)
5. Avoid prop drilling by using composition (Michael Jackson). Context is not the solution for every state sharing problem
6. Split giant useEffects to smaller independent ones (KCD: Myths about useEffect)
7. Extract logic to hooks and helper functions
8. Prefer having mostly primitives as dependencies to useCallback, useMemo, and useEffect
9. Do not put too many dependencies in useCallback, useMemo, and useEffect
10. For simplicity, instead of having many useStates, consider using useReducer if some values of your state rely on other values of your state and previous state
11. Context does not have to be global to your whole app. Put Context as low as possible in your component tree. Do this the same way you put variables, comments, states (and code in general) as close as possible to where they're relevant / being used.

💖 2.1 Avoid state management complexity by removing redundant states

When you have redundant states, some states may fall out of sync; you may forget to update them given a complex sequence of interactions. Aside from avoiding synchronization bugs, you'd notice that it's also easier to reason about and require less code. See also: KCD: Don't Sync State. Derive It!, Tic-Tac-Toe

🙈 Example 1

const TriangleInfo = () => {
  const [triangleInfo, setTriangleInfo] = useState<{a: number, b: number} | null>(null)
  const [hypotenuse, setHypotenuse] = useState<number | null>(null)
  const [perimeter, setPerimeter] = useState<number | null>(null)
  const [areas, setArea] = useState<number | null>(null)

  useEffect(() => {
    fetchTriangle().then(t => setTriangleInfo(t))
  }, [])

  useEffect(() => {
    if(!triangleInfo) {
      return
    }
    
    const { a, b } = triangleInfo
    const h = computeHypotenuse(a, b)
    setHypotenuse(h)
    const newArea = computeArea(a, b)
    setArea(newArea)
    const p = computePerimeter(a, b, h)
    setPerimeter(p)

  }, [triangleInfo])

  if (!triangleInfo) {
    return null
  }

  /*** show info here ****/
}

const TriangleInfo = () => {
  const [triangleInfo, setTriangleInfo] = useState<{
    a: number;
    b: number;
  } | null>(null)

  useEffect(() => {
    fetchTriangle().then((r) => setTriangleInfo(r))
  }, []);

  if (!triangleInfo) {
    return
  }

  const { a, b } = triangeInfo
  const area = computeArea(a, b)
  const hypotenuse = computeHypotenuse(a, b)
  const perimeter = computePerimeter(a, b, hypotenuse)
 
  /*** show info here ****/
};

🙈 Example 2

type SortBy = 'x' | 'y'
const toggle = (current: SortBy): SortBy => current === 'x' ? : 'y' : 'x'

const Points = () => {
  const [points, setPoints] = useState<{x: number, y: number}[]>([])
  const [filteredPoints, setFilteredPoints] = useState<{x: number, y: number}[]>([])
  const [sortedPoints, setSortedPoints] = useState<{x: number, y: number}[]>([])
  const [maxDistance, setMaxDistance] = useState<number>(100)
  const [sortBy, setSortBy] = useState<SortBy>('x')
  
  useEffect(() => {
    fetchPoints().then(r => setPoints(r))
  }, [])
  
  useEffect(() => {
    const sorted = sortPoints(points, sortBy)
    setSortedPoints(sorted)
  }, [sortBy, points])

  useEffect(() => {
    const filtered = sortedPoints.filter(p => getDistance(p.x, p.y) < maxDistance)
    setFilteredPoints(filtered)
  }, [sortedPoints, maxDistance])

  const otherSortBy = toggle(sortBy)
  const pointToDisplay = filteredPoints.map(
    p => <li key={`${p.x}|{p.y}`}>({p.x}, {p.y})</li>
  )

  return (
    <>
      <button onClick={() => setSortBy(otherSortBy)}>
        Sort by: {otherSortBy}
      <button>
      <button onClick={() => setMaxDistance(maxDistance + 10)}>
        Increase max distance
      <button>
      Showing only points that are less than {maxDistance} units away from origin (0, 0)
      Currently sorted by: '{sortBy}' (ascending)
      <ol>{pointToDisplay}</ol>
    </>
  )
}

// NOTE: You can also use useReducer instead
type SortBy = 'x' | 'y'
const toggle = (current: SortBy): SortBy => current === 'x' ? : 'y' : 'x'

const Points = () => {
  const [points, setPoints] = useState<{x: number, y: number}[]>([])
  const [maxDistance, setMaxDistance] = useState<number>(100)
  const [sortBy, setSortBy] = useState<SortBy>('x')

  useEffect(() => {
    fetchPoints().then(r => setPoints(r))
  }, [])
  

  const otherSortBy = toggle(sortBy)
  const filtedPoints = points.filter(p => getDistance(p.x, p.y) < maxDistance)
  const pointToDisplay = sortPoints(filteredPoints, sortBy).map(
    p => <li key={`${p.x}|{p.y}`}>({p.x}, {p.y})</li>
  )

  return (
    <>
      <button onClick={() => setSortBy(otherSortBy)}>
        Sort by: {otherSortBy} <button>
      <button onClick={() => setMaxDistance(maxDistance + 10)}>
        Increase max distance
      <button>
      Showing only points that are less than {maxDistance} units away from origin (0, 0)
      Currently sorted by: '{sortBy}' (ascending)
      <ol>{pointToDisplay}</ol>
    </>
  )
}

💖 2.2 Pass the banana, not the gorilla holding the banana and the entire jungle

You wanted a banana but what you got was a gorilla holding the banana and the entire jungle. - Joe Armstrong

To avoid falling into this trap, it's a good idea to pass mostly primitives (boolean, string, number, etc) types as props. (Passing primitives is also a good idea if you want to use React.memo for optimization)

A component should just know enough to do its job and nothing more. As much as possible, components should be able to collaborate with others without knowing what they are and what they do.

When we do this, the components will be more loosely coupled, the degree of dependency between two components will be lower. Loose coupling makes it easier to change, replace, or remove components without affecting other components. stackoverflow:2832017

🙈 Example

type Member = {
  id: string
  firstName: string
  lastName: string
  title: string
  imgUrl: string
  webUrl: string
  age: number
  bio: string
  /****** 100 more fields ******/
}

const Summary = ({ member } : { member: Member }) => {
  /*** include "the random styling feature" ***/
  return (
    <>
      <img src={member.imgUrl} />
      <a href={member.webUrl} >
        {member.title}. {member.firstName} {member.lastName}
      </a>
    </>
  )
}

const SeeMore = ({ member }: { member: Member }) => {
  const [seeMore, setSeeMore] = useState<boolean>(false)
  return (
    <>
      <button onClick={() => setSeeMore(!seeMore)}>
        See {seeMore ? "less" : "more"}
      </button>
      {seeMore && <>AGE: {member.age} | BIO: {member.bio}</>}
    </>
  )
}

const MemberCard = ({ id }: { id: string })) => {
  const member = useMember(id)
  return <><Summary member={member} /><SeeMore member={member} /></>
}

const Summary = ({ imgUrl, webUrl, header }: { imgUrl: string, webUrl: string, header: string }) => {
  /*** include "the random styling feature" ***/
  return (
    <>
      <img src={imgUrl} />
      <a href={webUrl}>{header}</a>
    </>
  )
}

const SeeMore = ({ componentToShow }: { componentToShow: ReactNode }) => {
  const [seeMore, setSeeMore] = useState<boolean>(false)
  return (
    <>
      <button onClick={() => setSeeMore(!seeMore)}>
        See {seeMore ? "less" : "more"}
      </button>
      {seeMore && <>{componentToShow}</>}
    </>
  )
}


const MemberCard = ({ id }: { id: string }) => {
  const { title, firstName, lastName, webUrl, imgUrl, age, bio } = useMember(id)
  const header = `${title}. ${firstName} ${lastName}`
  return (
    <>
      <Summary {...{ imgUrl, webUrl, header }} />
      <SeeMore componentToShow={<>AGE: {age} | BIO: {bio}</>} />
    </>
  )
}

Notice that in the ✅ "better" solution", SeeMore and Summary are components that can be used not just by Member. It can be used perhaps by other objects such as CurrentUser, Pet, Post... anything that needs those specific functionality.

💖 2.3 Keep your components small and simple

What is the single responsibility principle?

A component should have one and only one job. It should do the smallest possible useful thing. It only has responsibilities that fulfill its purpose.

A component with various responsibilities is difficult to reuse. If you want to reuse some but not all of its behavior, it's almost always impossible to just get what you need. It is also likely to be entangled with other code. Components that do one thing which isolate that thing from the rest of your application allows change without consequence and reuse without duplication.

How to know if your component has a single responsibility?

Try to describe that component in one sentence. If it is only responsible for one thing then it should be simple to describe. If it uses the word ‘and’ or ‘or’ then it is likely that your component fails this test.

Inspect the component's state, the props and hooks it consumes, as well as variables and methods declared inside the component (there shouldn't be too many). Ask yourself: Do these things actually work together to fulfill the component's purpose? If some of them don't, consider moving those somewhere else or breaking down your big component into smaller ones.

(The paragraphs above are based on my 2015 article: Three things I learned from Sandi Metz’s book as a non-Ruby programmer)

🙈 Example

type ShopCategoryTileProps = {
  isBooked: boolean
  icon: ReactNode
  label: string
  componentInsideModal?: ReactNode
  items?: {name: string, quantity: number}[]
}

const ShopCategoryTile = ({
  icon,
  label,
  items
  componentInsideModal,
}: ShopCategoryTileProps ) => {
  const [openDialog, setOpenDialog] = useState(false)
  const [hover, setHover] = useState(false)
  const disabled = !items || items.length  === 0
  return (
    <>
      <Tooltip title="Not Available" show={disabled}>
        <StyledButton
          className={disabled ? "grey" : isBooked ? "green" : "red" }
          disabled={disabled}
          onClick={() => disabled ? null : setOpenDialog(true) }
          onMouseEnter={() => disabled ? null : setHover(true)}
          onMouseLeave={() => disabled ? null : setHover(false)}
        >
          {icon}
          <StyledLabel>{label}<StyledLabel/>
          {!disabled && isBooked && <FaCheckCircle/>}
          {!disabled && hover && <WavingHand />}
        </StyledButton>
      </Tooltip>
      {componentInsideModal &&
        <Dialog open={openDialog} onClose={() => setOpenDialog(false)}>
          {componentInsideModal}
        </Dialog>
      }
    </>
  )
}

// split into two smaller components!

const DisabledShopCategoryTile = ({ icon, label }: { icon: ReactNode, label: string }) => {
  return (
    <Tooltip title="Not available">
      <StyledButton disabled={true} className="grey">
        {icon}
        <StyledLabel>{label}<StyledLabel/>
      </Button>
    </Tooltip>
  )
}

type ShopCategoryTileProps = {
  icon: ReactNode
  label: string
  isBooked: boolean
  componentInsideModal: ReactNode
}

const ShopCategoryTile = ({
  icon,
  label,
  isBooked,
  componentInsideModal,
}: ShopCategoryTileProps ) => {
  const [openDialog, setOpenDialog] = useState(false)
  const [hover, setHover] = useState(false)

  return (
    <>
      <StyledButton
        disabled={false}
        className={isBooked ? "green" : "red"}
        onClick={() => setOpenDialog(true) }
        onMouseEnter={() => setHover(true)}
        onMouseLeave={() => setHover(false)}
      >
        {icon}
        <StyledLabel>{label}<StyledLabel/>
        {isBooked && <FaCheckCircle/>}
        {hover && <WavingHand />}
      </StyledButton>
      {openDialog &&
        <Dialog onClose={() => setOpenDialog(false)}>
          {componentInsideModal}
        </Dialog>
      }}
    </>
  )
}

Note: The example above is a simplified version of a component that I've actually seen in production

const ShopCategoryTile = ({
  item,
  offers,
}: {
  item: ItemMap;
  offers?: Offer;
}) => {
  const dispatch = useDispatch();
  const location = useLocation();
  const history = useHistory();
  const { items } = useContext(OrderingFormContext)
  const [openDialog, setOpenDialog] = useState(false)
  const [hover, setHover] = useState(false)
  const isBooked =
    !item.disabled && !!items?.some((a: Item) => a.itemGroup === item.group)
  const isDisabled = item.disabled || !offers
  const RenderComponent = item.component

  useEffect(() => {
    if (openDialog && !location.pathname.includes("item")) {
      setOpenDialog(false)
    }
  }, [location.pathname]);
  const handleClose = useCallback(() => {
    setOpenDialog(false)
    history.goBack()
  }, [])

  return (
    <GridStyled
      xs={6}
      sm={3}
      md={2}
      item
      booked={isBooked}
      disabled={isDisabled}
    >
      <Tooltip
        title="Not available"
        placement="top"
        disableFocusListener={!isDisabled}
        disableHoverListener={!isDisabled}
        disableTouchListener={!isDisabled}
      >
        <PaperStyled
          disabled={isDisabled}
          elevation={isDisabled ? 0 : hover ? 6 : 2}
        >
          <Wrapper
            onClick={() => {
              if (isDisabled) {
                return;
              }
              dispatch(push(ORDER__PATH));
              setOpenDialog(true);
            }}
            disabled={isDisabled}
            onMouseEnter={() => !isDisabled && setHover(true)}
            onMouseLeave={() => !isDisabled && setHover(false)}
          >
            {item.icon}
            <Typography variant="button">{item.label}</Typography>
            <CheckIconWrapper>
              {isBooked && <FaCheckCircle size="26" />}
            </CheckIconWrapper>
          </Wrapper>
        </PaperStyled>
      </Tooltip>
      <Dialog fullScreen open={openDialog} onClose={handleClose}>
        {RenderComponent && (
          <RenderComponent item={item} offer={offers} onClose={handleClose} />
        )}
      </Dialog>
    </GridStyled>
  )
}

💖 2.4 Duplication is far cheaper than the wrong abstraction

Avoid premature / inappropriate generalization. If your implementation for a simple feature requires a huge overhead, consider other options. I highly recommend reading Sandi Metz: The Wrong Abstraction.

A particular type of complexity is over-engineering, where developers have made the code more generic than it needs to be, or added functionality that isn’t presently needed by the system. Encourage developers to solve the problem they know needs to be solved now, not the problem that the developer speculates might need to be solved in the future. The future problem should be solved once it arrives and you can see its actual shape and requirements in the physical universe. - Google Engineering Practices: What to look for in a code review

See also: KCD: AHA Programming, C2 Wiki: Contrived Interfaces/The Expensive Setup Smell/Premature Generalization

🧘 3. Performance tips

Premature optimization is the root of all evil - Tony Hoare

One accurate measurement is worth a thousand expert opinions. - Grace Hopper

TL;DR

1. If you think it’s slow, prove it with a benchmark. "In the face of ambiguity, refuse the temptation to guess." The profiler of React Developer Tools (Chrome extension) is your friend!
2. Use useMemo mostly just for expensive calculations
3. If you're going to use React.memo, useMemo, and useCallback for reducing re-renders, they shouldn't have many dependencies and the dependencies should be mostly primitive types.
4. Make sure your React.memo, useCallback or useMemo is doing what you think it's doing (is it really preventing rerendering? Can you demonstrate empirically that using them on your case has significant performance gains? Memoization can sometimes make your app worse, so keep an eye on that!)
5. Stop punching yourself every time you blink (fix slow renders before fixing rerenders)
6. Putting your state as close as possible to where it's being used will not only make your code so much easier to read but it would also make your app faster (state colocation)
7. Context should be logically separated, do not add too many values in one context provider. If any of the values of your context changes, all components consuming that context also rerenders even if those components don't use the specific value that was actually changed.
8. You can optimize context by separating the state and the dispatch function
9. Know the terms lazy loading and bundle/code splitting
10. Window large lists (with tannerlinsley/react-virtual or similar)
11. A smaller bundle size usually also means a faster app. You can visualize the code bundles you've generated with tools such as source-map-explorer or @next/bundle-analyzer (for NextJS).
12. If you're going to use a package for your forms, I recommend react-hook-forms. I think it is a great balance of good performance and good developer experience.

🧘 4. Testing principles

Write tests. Not too many. Mostly integration. - Guillermo Rauch

TL;DR

1. Your tests should always resemble the way your software is used
2. Make sure that you're not testing implementation details - things which users do not use, see, or even know about
3. If your tests don't make you confident that you didn't break anything, then they didn't do their (one and only) job
4. You'll know you implemented correct tests when you rarely have to change tests when you refactor code given the same user behavior
5. For the front-end, you don't need 100% code coverage, about 70% is probably good enough. Tests should make you more productive not slow you down. Maintaining tests can slow you down. You get diminishing returns on adding more tests after a certain point
6. I like using Jest, React testing library, Cypress, and Mock service worker

🧘 5. Insights shared by others

If you'd like to share some of the things you think about when you write React code that I didn't touch upon, you can submit a PR and add them to this section. Thanks for taking the time to share your ideas!

Josh W Comeau

A similar principle I feel much more strongly about is not to pass setters that have too much power. For example, I might pass an updateEmail function instead of a setUser function. I don't want random components to be able to change things they don't have any business changing.

Not only should a component have a single responsibility, it should also have a clear spot on the spectrum of abstraction. On one end, we have generic building blocks like <Button>, <Heading>, <Modal>. On the other end, we have one-off templates like <Homepage> and <ContactForm>. Every component should have a clear spot on this spectrum. A <Button> component shoudn't have a user prop, since users are a higher-abstract concept and Button is a low-abstract component.

(Note, the above is taken from his response to my email... I really appreciate that he took the time to share his ideas 🙂)