Export multiple functions from a file in React.js

Export multiple functions from a file in React.js #

Use named exports to export multiple functions in React, e.g. export function A() {} and export function B() {}. The exported functions can be imported by using a named import as import {A, B} from './another-file'. You can have as many named exports as necessary in a single file.

Here is an example of exporting multiple functions from a file called Boxes.js.

Boxes.js

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// 👇️ named export
export function SmallBox() {
  return (
    <div
      style={{
        backgroundColor: 'salmon',
        color: 'white',
        height: '100px',
        width: '100px',
      }}
    >
      Small Box
    </div>
  );
}

// 👇️ named export
export const BigBox = () => {
  return (
    <div
      style={{
        padding: '30px',
        backgroundColor: 'lime',
        color: 'white',
        height: '200px',
        width: '200px',
      }}
    >
      Big Box
    </div>
  );
};

Note that using the export keyword on the same line as the function's definition is the same as exporting the functions as an object after they have been declared.

Boxes.js

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function SmallBox() {
  return (
    <div
      style={{
        backgroundColor: 'salmon',
        color: 'white',
        height: '100px',
        width: '100px',
      }}
    >
      Small Box
    </div>
  );
}

const BigBox = () => {
  return (
    <div
      style={{
        padding: '30px',
        backgroundColor: 'lime',
        color: 'white',
        height: '200px',
        width: '200px',
      }}
    >
      Big Box
    </div>
  );
};

// 👇️ named exports
export {SmallBox, BigBox};

Here is how we would import the functions in a file called App.js.

App.js

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import {SmallBox, BigBox} from './Boxes';

export default function App() {
  return (
    <div>
      <SmallBox />

      <BigBox />
    </div>
  );
}

Make sure to correct the path that points to the Boxes.js module if you have to. The example above assumes that Boxes.js and App.js are located in the same directory.

For example, if you were importing from one directory up, you would do import {SmallBox, BigBox} from '../Boxes'.

We wrapped the names of the functions in curly braces when importing them - this is called a named import.

The import/export syntax is called ES6 Modules in JavaScript.

In order to be able to import a function from a different file, it has to be exported using a named or default export.

The example above uses named exports and named imports.

The main difference between named and default exports and imports is - you can have multiple named exports per file, but you can only have a single default export.

If you try to use multiple default exports in a single file, you would get an error.

Boxes.js

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export default function SmallBox() {
  return (
    <div
      style={{
        backgroundColor: 'salmon',
        color: 'white',
        height: '100px',
        width: '100px',
      }}
    >
      Small Box
    </div>
  );
}

const BigBox = () => {
  return (
    <div
      style={{
        padding: '30px',
        backgroundColor: 'lime',
        color: 'white',
        height: '200px',
        width: '200px',
      }}
    >
      Big Box
    </div>
  );
};

// ⛔️ Parsing error: Only one default export allowed per module.
export default BigBox

IMPORTANT: If you are exporting a variable (or an arrow function) as a default export, you have to declare it on 1 line and export it on the next. You can't declare and default export a variable on the same line.

Having said that, you can use 1 default export and as many named exports as you need in a single file.

Let's look at an example that exports multiple functions and uses both - default and named exports.

Boxes.js

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// 👇️ default export
export default function SmallBox() {
  return (
    <div
      style={{
        backgroundColor: 'salmon',
        color: 'white',
        height: '100px',
        width: '100px',
      }}
    >
      Small Box
    </div>
  );
}

// 👇️ named export
export const BigBox = () => {
  return (
    <div
      style={{
        padding: '30px',
        backgroundColor: 'lime',
        color: 'white',
        height: '200px',
        width: '200px',
      }}
    >
      Big Box
    </div>
  );
};

And here is how you would import the two functions.

App.js

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// 👇️ default and named imports
import SmallBox, {BigBox} from './Boxes';

export default function App() {
  return (
    <div>
      <SmallBox />

      <BigBox />
    </div>
  );
}

Notice that we didn't wrap the default import in curly braces.

We used a default import to import the SmallBox function and a named import to import the BigBox function.

Note that you can only have a single default export per file, but you can have as many named exports as necessary.

In my experience, most real world codebases exclusively use named exports and imports because they make it easier to leverage your IDE for autocompletion and auto-imports.

You also don't have to think about which members are exported with a default or named export.

Export multiple functions from a file in React.js

Export multiple functions from a file in React.js #

Borislav Hadzhiev