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Fabio Biondi
Fabio Biondi

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How to create React UIKIT components in TypeScript that extends native HTML Elements

In the front-end ecosystem, UiKits are collections of utilities and several components, such as:

  • <Card />
  • <TabBar />
  • <Carousel />
  • <Row /> and <Col />
  • <GoogleMap />

Each component has usually its own custom layout and could accepts several properties. For example, a <GoogleMap /> component could accept the "coordinates" and a "zoom" value as properties:

<GoogleMap coords={coords} zoom={zoom} />
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Sometimes we need to create components whose layout is created from scratch. In other cases their layout may be based of native elements.
Some examples:

  • <MyButton />: that extends <button> element capabilities
  • <MyImg />: that extends <img> element
  • and so on.

Let's imagine a button component that must display an icon next to the label that I can use as the code below:

<MyButton icon="💩"> CLICK ME </MyButton>
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This component should accept the icon and children properties and its definition may looks like the following:

interface MyButtonProps {
  icon: string;
}

function MyButton(props: PropsWithChildren<MyButtonProps>) {
  const { icon, children } = props;
  return <button className="btn btn-primary">
    {icon} {children}
  </button>
}
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So we can use the component in this way:

<MyButton icon="💩"> DO SOMETHING</icon>
<MyButton icon="😱"> CLICK ME</icon>
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Button Preview


In order to be more flexible, the <MyButton /> component should also accepts all the native button properties. For example we may need to listen the onClick event or set the disabled attribute:

<MyButton icon="💩" onClick={() => {}} disabled />
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So we can simply add them to the Component's Property Type and apply them as attributes of the <button> element:

// 1. Add the properties 
interface MyButtonProps {
  icon: string;  
  disabled: boolean;   // ➡️ native prop
  onClick: (e: React.MouseEvent) => void; // ➡️ native prop
  // ➡️ other native props
}

function MyButton(props: PropsWithChildren<MyButtonProps) {

  const { icon, children, onClick, disabled } = props;
  // 2. apply all props one by one
  return <button disabled={disabled} onClick={onClick} className="btn btn-primary">
    {icon}
    {children}
  </button>
}
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What could I do to avoid manually passing all properties of a native button?

There is a trick!

We can simply use an intersection type to combine our custom props with all the HTMLButtonElement properties to automatically support all native buttons properties:

export function MyButton(
  props: PropsWithChildren<MyButtonProps & React.ButtonHTMLAttributes<HTMLButtonElement>>
) { 
 // ... component here ...
}
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Now your component supports all buttons properties and we can apply them simply using this trick:

// apply all props as button attributes
return <button className="btn btn-primary" {...props}>
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However icon and children are not valid button's properties so we can use destructuring to create a rest property that contain all the properties except them:

  const { icon, children, ...rest } = props;

  // Now we apply all props except icons and children
  return <button className="btn btn-primary" {...rest}>
    {icon}
    {children}
  </button>
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And that's all.
Here the final source code to create a button that support icon, children and all native button properties:

import { PropsWithChildren } from 'react';

interface MyButtonProps {
  icon: string;
}
export function MyButton(
  props: PropsWithChildren<MyButtonProps & React.ButtonHTMLAttributes<HTMLButtonElement>>
) {
  const { icon, children, ...rest } = props;
  return <button className="btn btn-primary" {...rest}>
    {icon}
    {children}
  </button>
}

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USAGE EXAMPLE:

<MyButton 
  icon="💩" 
  type="submit"
  disabled={...} 
  onClick={...} 
  onMouseOver={...} 
> CLICK ME </MyButton>
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You can also be interested to read this article:
Create a React / TypeScript Generic component


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