React Components Overview

Reusable function components for common UI patterns

This collection provides production-ready React function components for common UI patterns. All components use modern React hooks and follow best practices.

Component Categories

Interactive

User input and interaction components

• Toggle
• Star Rating
• Password Revealer

Data Display

Components for displaying data

• DataTable
• DataList
• TreeView

Feedback

User feedback components

• Tooltip
• Alert
• Modal Dialog

Quick Examples

Toggle Component

A simple toggle component that acts as a visual checkbox:

const Toggle = ({ defaultToggled = false }) => {
  const [isToggleOn, setIsToggleOn] = React.useState(defaultToggled);

  return (
    <label className={isToggleOn ? 'toggle on' : 'toggle off'}>
      <input
        type="checkbox"
        checked={isToggleOn}
        onChange={() => setIsToggleOn(!isToggleOn)}
      />
      {isToggleOn ? 'ON' : 'OFF'}
    </label>
  );
};

CSS for Toggle Component

.toggle input[type="checkbox"] {
  display: none;
}

.toggle.on {
  background-color: green;
}

.toggle.off {
  background-color: red;
}

Star Rating Component

Create an interactive star rating component:

const Star = ({ marked, starId }) => {
  return (
    <span data-star-id={starId} className="star" role="button">
      {marked ? '\u2605' : '\u2606'}
    </span>
  );
};

const StarRating = ({ value }) => {
  const [rating, setRating] = React.useState(parseInt(value) || 0);
  const [selection, setSelection] = React.useState(0);

  const hoverOver = event => {
    let val = 0;
    if (event && event.target && event.target.getAttribute('data-star-id'))
      val = event.target.getAttribute('data-star-id');
    setSelection(val);
  };
  
  return (
    <div
      onMouseOut={() => hoverOver(null)}
      onClick={e => setRating(e.target.getAttribute('data-star-id') || rating)}
      onMouseOver={hoverOver}
    >
      {Array.from({ length: 5 }, (v, i) => (
        <Star
          starId={i + 1}
          key={`star_${i + 1}`}
          marked={selection ? selection >= i + 1 : rating >= i + 1}
        />
      ))}
    </div>
  );
};

The StarRating component uses two state variables: rating for the actual value and selection for hover preview.

Data Display Components

DataList Component

Transform an array into an ordered or unordered list:

const DataList = ({ isOrdered = false, data }) => {
  const list = data.map((val, i) => <li key={`${i}_${val}`}>{val}</li>);
  return isOrdered ? <ol>{list}</ol> : <ul>{list}</ul>;
};

// Usage
const names = ['John', 'Paul', 'Mary'];

ReactDOM.createRoot(document.getElementById('root')).render(
  <>
    <DataList data={names} />
    <DataList data={names} isOrdered />
  </>
);

DataTable Component

Display array data in a table format:

const DataTable = ({ data }) => {
  return (
    <table>
      <thead>
        <tr>
          <th>ID</th>
          <th>Value</th>
        </tr>
      </thead>
      <tbody>
        {data.map((val, i) => (
          <tr key={`${i}_${val}`}>
            <td>{i}</td>
            <td>{val}</td>
          </tr>
        ))}
      </tbody>
    </table>
  );
};

MappedTable Component

Create a dynamic table from an array of objects:

const MappedTable = ({ data, propertyNames }) => {
  let filteredData = data.map(v =>
    Object.keys(v)
      .filter(k => propertyNames.includes(k))
      .reduce((acc, key) => ((acc[key] = v[key]), acc), {})
  );
  
  return (
    <table>
      <thead>
        <tr>
          {propertyNames.map(val => (
            <th key={`h_${val}`}>{val}</th>
          ))}
        </tr>
      </thead>
      <tbody>
        {filteredData.map((val, i) => (
          <tr key={`i_${i}`}>
            {propertyNames.map(p => (
              <td key={`i_${i}_${p}`}>{val[p]}</td>
            ))}
          </tr>
        ))}
      </tbody>
    </table>
  );
};

// Usage
const people = [
  { name: 'John', surname: 'Smith', age: 42 },
  { name: 'Adam', surname: 'Smith', gender: 'male' }
];
const propertyNames = ['name', 'surname', 'age'];

ReactDOM.createRoot(document.getElementById('root')).render(
  <MappedTable data={people} propertyNames={propertyNames} />
);

The MappedTable component does not work with nested objects and will break if there are nested objects in the specified properties.

Feedback Components

Tooltip Component

Display contextual information on hover:

const Tooltip = ({ children, text, ...rest }) => {
  const [show, setShow] = React.useState(false);

  return (
    <div className="tooltip-container">
      <div className={show ? 'tooltip-box visible' : 'tooltip-box'}>
        {text}
        <span className="tooltip-arrow" />
      </div>
      <div
        onMouseEnter={() => setShow(true)}
        onMouseLeave={() => setShow(false)}
        {...rest}
      >
        {children}
      </div>
    </div>
  );
};

Alert Component

Show dismissible alerts with animations:

const Alert = ({ isDefaultShown = false, timeout = 250, type, message }) => {
  const [isShown, setIsShown] = React.useState(isDefaultShown);
  const [isLeaving, setIsLeaving] = React.useState(false);

  let timeoutId = null;

  React.useEffect(() => {
    setIsShown(true);
    return () => {
      clearTimeout(timeoutId);
    };
  }, [isDefaultShown, timeout, timeoutId]);

  const closeAlert = () => {
    setIsLeaving(true);
    timeoutId = setTimeout(() => {
      setIsLeaving(false);
      setIsShown(false);
    }, timeout);
  };

  return (
    isShown && (
      <div
        className={`alert ${type} ${isLeaving ? 'leaving' : ''}`}
        role="alert"
      >
        <button className="close" onClick={closeAlert} />
        {message}
      </div>
    )
  );
};

Modal Dialog Component

Create accessible modal dialogs with keyboard support:

const Modal = ({ isVisible = false, title, content, footer, onClose }) => {
  const keydownHandler = ({ key }) => {
    switch (key) {
      case 'Escape':
        onClose();
        break;
      default:
    }
  };

  React.useEffect(() => {
    document.addEventListener('keydown', keydownHandler);
    return () => document.removeEventListener('keydown', keydownHandler);
  });

  return !isVisible ? null : (
    <div className="modal" onClick={onClose}>
      <div className="modal-dialog" onClick={e => e.stopPropagation()}>
        <div className="modal-header">
          <h3 className="modal-title">{title}</h3>
          <span className="modal-close" onClick={onClose}>
            &times;
          </span>
        </div>
        <div className="modal-body">
          <div className="modal-content">{content}</div>
        </div>
        {footer && <div className="modal-footer">{footer}</div>}
      </div>
    </div>
  );
};

// Usage
const App = () => {
  const [isModal, setModal] = React.useState(false);
  return (
    <>
      <button onClick={() => setModal(true)}>Click Here</button>
      <Modal
        isVisible={isModal}
        title="Modal Title"
        content={<p>Add your content here</p>}
        footer={<button>Cancel</button>}
        onClose={() => setModal(false)}
      />
    </>
  );
};

The Modal component handles ESC key presses and click-outside to close, providing a better user experience.

Component Design Patterns

Controlled Components

Use state to control component values, making them predictable and testable.

Composition

Build complex components by composing simpler ones, like Star and StarRating.

Props Destructuring

Destructure props for cleaner code and use spread operators for flexibility.

Accessibility

Include ARIA attributes and keyboard support for better accessibility.

Best Practices

1. State Management

   Keep state as close as possible to where it’s used. Lift state up only when necessary.

2. Event Handlers

   Use cleanup functions to remove event listeners when components unmount.

3. Key Props

   Always provide unique, stable key props when rendering lists of components.

4. CSS Separation

   Keep CSS separate from component logic for better maintainability.

Next Steps

View Examples

See complete component implementations with styling

Learn Testing

Discover how to test these components