lbry-desktop/ui/component/channelThumbnail/view.jsx

// @flow
import React from 'react';
import { parseURI } from 'lbry-redux';
import classnames from 'classnames';
import Gerbil from './gerbil.png';

type Props = {
  thumbnail: ?string,
  uri: ?string,
  className?: string,
  thumbnailPreview: ?string,
  obscure?: boolean,
};

function ChannelThumbnail(props: Props) {
  const { thumbnail, uri, className, thumbnailPreview, obscure } = props;
  // Generate a random color class based on the first letter of the channel name
  let initializer;
  if (thumbnail) {
    const { channelName } = parseURI(uri);
    initializer = channelName.charCodeAt(0) - 65; // will be between 0 and 57
  } else {
    // if we want to default a thumbnail
    initializer = Math.floor(Math.random() * 104729); // 10000th prime number
  }
  const colorClassName = `channel-thumbnail__default--${initializer % 4}`;
  const showThumb = !obscure && !!thumbnail;
  return (
    <div
      className={classnames('channel-thumbnail', className, {
        [colorClassName]: !showThumb,
      })}
    >
      {!showThumb && <img className="channel-thumbnail__default" src={thumbnailPreview || Gerbil} />}
      {showThumb && <img className="channel-thumbnail__custom" src={thumbnailPreview || thumbnail} />}
    </div>
  );
}

export default ChannelThumbnail;