hyper/lib/components/notification.tsx

import React, {forwardRef, useEffect, useRef, useState} from 'react';
import type {NotificationProps} from '../../typings/hyper';

const Notification = forwardRef<HTMLDivElement, React.PropsWithChildren<NotificationProps>>((props, ref) => {
  const dismissTimer = useRef<NodeJS.Timeout | undefined>(undefined);
  const [dismissing, setDismissing] = useState(false);

  useEffect(() => {
    setDismissTimer();
  }, []);

  useEffect(() => {
    // if we have a timer going and the notification text
    // changed we reset the timer
    resetDismissTimer();
    setDismissing(false);
  }, [props.text]);

  const handleDismiss = () => {
    setDismissing(true);
  };

  const onElement = (el: HTMLDivElement | null) => {
    if (el) {
      el.addEventListener('webkitTransitionEnd', () => {
        if (dismissing) {
          props.onDismiss();
        }
      });
      const {backgroundColor} = props;
      if (backgroundColor) {
        el.style.setProperty('background-color', backgroundColor, 'important');
      }

      if (ref) {
        if (typeof ref === 'function') ref(el);
        else ref.current = el;
      }
    }
  };

  const setDismissTimer = () => {
    if (typeof props.dismissAfter === 'number') {
      dismissTimer.current = setTimeout(() => {
        handleDismiss();
      }, props.dismissAfter);
    }
  };

  const resetDismissTimer = () => {
    clearTimeout(dismissTimer.current);
    setDismissTimer();
  };

  useEffect(() => {
    return () => {
      clearTimeout(dismissTimer.current);
    };
  }, []);

  const {backgroundColor, color} = props;
  const opacity = dismissing ? 0 : 1;
  return (
    <div ref={onElement} style={{opacity, backgroundColor, color}} className="notification_indicator">
      {props.customChildrenBefore}
      {props.children || props.text}
      {props.userDismissable ? (
        <a className="notification_dismissLink" onClick={handleDismiss} style={{color: props.userDismissColor}}>
          [x]
        </a>
      ) : null}
      {props.customChildren}

      <style jsx>{`
        .notification_indicator {
          display: inline-block;
          cursor: default;
          -webkit-user-select: none;
          background: rgba(255, 255, 255, 0.2);
          padding: 8px 14px 9px;
          margin-left: 10px;
          transition: 150ms opacity ease;
          color: #fff;
          font-size: 12px;
          font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell',
            'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
        }

        .notification_dismissLink {
          position: relative;
          left: 4px;
          cursor: pointer;
          font-weight: 600;
          color: currentColor;
          transition: font-weight 0.1s ease-in-out;
        }

        .notification_dismissLink:hover,
        .notification_dismissLink:focus {
          font-weight: 900;
        }
      `}</style>
    </div>
  );
});

Notification.displayName = 'Notification';

export default Notification;