Tapajyoti Bose

Posted on Jul 17, 2022 • Updated on Oct 24, 2023

7 Tips for Clean React TypeScript Code you Must Know 🧹✨

#react #javascript #typescript #webdev

Clean code isn't code that just works. It refers to neatly organized code which is easy to read, simple to understand and a piece of cake to maintain.

Let's take a look at some of the best practices for clean code in React, which can take the ease of maintaining your code to the moon! 🚀🌕

1. Provide explicit types for all values

Quite often while using TypeScript a lot of people skip out on providing explicit types for values, thus missing out on the true benefit TypeScript has to offer. Often these can be seen in code-base:

Bad Example 01:

const Component = ({ children }: any) => {
  // ...
};

Bad Example 02:

const Component = ({ children }: object) => {
  // ...
};

Instead using a properly defined interface would make your life so much easier, with the editor providing you accurate suggestions.

Good Example:

import { ReactNode } from "react";

interface ComponentProps {
  children: ReactNode;
}

const Component = ({ children }: ComponentProps) => {
  // ...
};

2. Take the previous state into account while updating the state

It is always advisable to set state as a function of the previous state if the new state relies on the previous state. React state updates can be batched, and not writing your updates this way can lead to unexpected results.

Bad Example:

import React, { useState } from "react";

export const App = () => {
  const [isDisabled, setIsDisabled] = useState(false);

  const toggleButton = () => {
    setIsDisabled(!isDisabled);
  };

  // here toggling twice will yeild the same result
  // as toggling once
  const toggleButtonTwice = () => {
    toggleButton();
    toggleButton();
  };

  return (
    <div>
      <button disabled={isDisabled}>
        I'm {isDisabled ? "disabled" : "enabled"}
      </button>
      <button onClick={toggleButton}>
        Toggle button state
      </button>
      <button onClick={toggleButtonTwice}>
        Toggle button state 2 times
      </button>
    </div>
  );
};

Good example:

import React, { useState } from "react";

export const App = () => {
  const [isDisabled, setIsDisabled] = useState(false);

  const toggleButton = () => {
    setIsDisabled((isDisabled) => !isDisabled);
  };

  const toggleButtonTwice = () => {
    toggleButton();
    toggleButton();
  };

  return (
    <div>
      <button disabled={isDisabled}>
        I'm {isDisabled ? "disabled" : "enabled"}
      </button>
      <button onClick={toggleButton}>
        Toggle button state
      </button>
      <button onClick={toggleButtonTwice}>
        Toggle button state 2 times
      </button>
    </div>
  );
};

3. Keep your files lean & clean

Keeping your files atomic and lean makes debugging, maintaining, and even finding the files a walk in the park!

Bad Example:

// src/App.tsx
export default function App() {
  const posts = [
    {
      id: 1,
      title: "How to write clean react code",
    },
    {
      id: 2,
      title: "Eat, sleep, code, repeat",
    },
  ];

  return (
    <main>
      <nav>
        <h1>App</h1>
      </nav>
      <ul>
        {posts.map((post) => (
          <li key={post.id}>
            {post.title}
          </li>
        ))}
      </ul>
    </main>
  );
}

Good Example:

// src/App.tsx
export default function App() {
  return (
    <main>
      <Navigation title="App" />
      <Posts />
    </main>
  );
}

// src/components/Navigation.tsx
interface NavigationProps {
  title: string;
}

export default function Navigation({ title }: NavigationProps) {
  return (
    <nav>
      <h1>{title}</h1>
    </nav>
  );
}

// src/components/Posts.tsx
export default function Posts() {
  const posts = [
    {
      id: 1,
      title: "How to write clean react code",
    },
    {
      id: 2,
      title: "Eat, sleep, code, repeat",
    },
  ];

  return (
    <ul>
      {posts.map((post) => (
        <Post key={post.id} title={post.title} />
      ))}
    </ul>
  );
}

// src/components/Post.tsx
interface PostProps {
  title: string;
}

export default function Post({ title }: PostProps) {
  return <li>{title}</li>;
}

4. Use Enums or Constant Objects for values with multiple states

The process of managing variables that can take multiple states can be eased a lot by using Enums or Constant Objects.

Bad Example:

import React, { useState } from "react";

export const App = () => {
  const [status, setStatus] = useState("Pending");

  return (
    <div>
      <p>{status}</p>
      <button onClick={() => setStatus("Pending")}>
        Pending
      </button>
      <button onClick={() => setStatus("Success")}>
        Success
      </button>
      <button onClick={() => setStatus("Error")}>
        Error
      </button>
    </div>
  );
};

Good Example:

import React, { useState } from "react";

enum Status {
  Pending = "Pending",
  Success = "Success",
  Error = "Error",
}
// OR
// const Status = {
//   Pending: "Pending",
//   Success: "Success",
//   Error: "Error",
// } as const;

export const App = () => {
  const [status, setStatus] = useState(Status.Pending);

  return (
    <div>
      <p>{status}</p>
      <button onClick={() => setStatus(Status.Pending)}>
        Pending
      </button>
      <button onClick={() => setStatus(Status.Success)}>
        Success
      </button>
      <button onClick={() => setStatus(Status.Error)}>
        Error
      </button>
    </div>
  );
};

5. Use TS-free TSX as much as possible

How can TSX be TS-free? 🤔

Relax, we are talking only about the Markup part NOT the entire component. Keeping it function-free makes the component easier to understand.

Bad Example:

const App = () => {
  return (
    <div>
      <button
        onClick={() => {
          // ...
        }}
      >
        Toggle Dark Mode
      </button>
    </div>
  );
};

Good Example:

const App = () => {
  const handleDarkModeToggle = () => {
    // ...
  };

  return (
    <div>
      <button onClick={handleDarkModeToggle}>
        Toggle Dark Mode
      </button>
    </div>
  );
};

NOTE: If the logic is a one-liner, then using it in the TSX is quite acceptable.

6. Elegantly Conditionally Rendering Elements

Conditionally rendering elements is one of the most common tasks in React, thus using clean conditionals is a necessity.

Bad Example:

const App = () => {
  const [isTextShown, setIsTextShown] = useState(false);

  const handleToggleText = () => {
    setIsTextShown((isTextShown) => !isTextShown);
  };

  return (
    <div>
      {isTextShown ? <p>Now You See Me</p> : null}

      {isTextShown && <p>`isTextShown` is true</p>}
      {!isTextShown && <p>`isTextShown` is false</p>}

      <button onClick={handleToggleText}>Toggle</button>
    </div>
  );
};

Good Example:

const App = () => {
  const [isTextShown, setIsTextShown] = useState(false);

  const handleToggleText = () => {
    setIsTextShown((isTextShown) => !isTextShown);
  };

  return (
    <div>
      {isTextShown && <p>Now You See Me</p>}

      {isTextShown ? (
        <p>`isTextShown` is true</p>
      ) : (
        <p>`isTextShown` is false</p>
      )}

      <button onClick={handleToggleText}>Toggle</button>
    </div>
  );
};

7. Use JSX shorthands

Boolean Props

A truthy prop can be provided to a component with just the prop name without a value like this: truthyProp. Writing it like truthyProp={true} is unnecessary.

Bad Example:

interface TextFieldProps {
  fullWidth: boolean;
}

const TextField = ({ fullWidth }: TextFieldProps) => {
  // ...
};

const App = () => {
  return <TextField fullWidth={true} />;
};

Good Example:

interface TextFieldProps {
  fullWidth: boolean;
}

const TextField = ({ fullWidth }: TextFieldProps) => {
  // ...
};

const App = () => {
  return <TextField fullWidth />;
};

String Props

A String Prop value can be provided in double-quotes without the use of curly braces or backticks.

Bad example:

interface AvatarProps {
  username: string;
}

const Avatar = ({ username }: AvatarProps) => {
  // ...
};

const Profile = () => {
  return <Avatar username={"John Wick"} />;
};

Good example:

interface AvatarProps {
  username: string;
}

const Avatar = ({ username }: AvatarProps) => {
  // ...
};

const Profile = () => {
  return <Avatar username="John Wick" />;
};

Undefined Props

Just like basic TypeScript/JavaScript, if a prop is not provided a value, it will be undefined.

Bad Example:

interface AvatarProps {
  username?: string;
}

const Avatar = ({ username }: AvatarProps) => {
  // ...
};

const Profile = () => {
  return <Avatar username={undefined} />;
};

Good Example:

interface AvatarProps {
  username?: string;
  // OR `username: string | undefined`
}

const Avatar = ({ username }: AvatarProps) => {
  // ...
};

const Profile = () => {
  return <Avatar />;
};

Now you too know how to write clean TSX!

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Top comments (21)

Yusub Yacob • Jan 4 '23

you are the best man .

Yuwang Cai • Jul 17 '22

Great article!
A little complain about conditional rendering in React: Even though ternary expression is the best solution I know, these brackets still makes my code looking like a mess. And I really love the v-if directive in vue, which surprises me a lot at first glance.

Rense Bakker • Jul 17 '22

You can use this as a type for your components that use children:

function My component({children, otherProp}:React.PropsWithChildren<{otherProp:string}>){
  // ...
}

Raí B. Toffoletto • Jul 19 '22

Well remembered, the setter of useState is already memoised, no need to wrap in a usrCallback.

Thanks for the article @ruppysuppy and the tips @lukeshiru

Akash • Jul 24 '22 • Edited

I am in love with the variable name 'truthyProp' lol
I think one of the weird thing Software Developers develop over time is admiration towards amazing variable names. Whenever I name one or see one, I get so happy and obsessed over it XD. It gives such a pleasurable feeling haha

Elijah Trillionz • Jul 18 '22

A really good writeup.
Thanks for this article.
I like the fact that you made bad examples and good examples, so I can see the "me" now, and the "me" I ought to be 😁.

Soldeplata Saketos • Jul 21 '22

For point #7 I would even add:
"Don't set unneeded falsey values, as they render as attributes in HTML"
instead of

type TextFieldProps = {
    fullWidth?: boolean;
};

const TextField = ({ fullWidth = false }: TextFieldProps) => {};

const App = () => <TextField fullWidth />;

which would eventually render into:

<input full-width="false"/>

leave it as undefined:

type TextFieldProps = {
    fullWidth?: boolean;
};

const TextField = ({ fullWidth }: TextFieldProps) => {};

const App = () => <TextField fullWidth />;

so it can skip the attribute in the HTML

Andrew Baisden • Jul 23 '22

Dope list thanks for creating it!

mako • Jul 17 '22

This is really nice

MajScript • Jul 17 '22

Nice!

Akshay S • Jul 17 '22

`import { ReactNode ,FC } from "react";

interface ComponentProps {
children: ReactNode;
}

const Component:FC = ({ children }) => {
// ...
};`

This seems more sensible

Aaron Reisman • Jul 19 '22

fwiw, you shouldn't be using interfaces unless you want to enhance a type.

e.g.:

interface Example {}

interface Example {
    foo: 'bar';
}

interface Example {
    baz: 'qux';
}

type Foo = Example['foo'];
type Baz = Example['baz'];


// @ts-expect-error TExample is defined
type TExample = {}

// @ts-expect-error TExample cannot be redefined
type TExample = {
    foo: 'bar';
}

Wilmela • Jul 17 '22

Very well written, thanks. However on point no. 3. When you have a simple component you won't be using else where, doesn't it make sense creating it in the same file instead of a whole new file?