cli-highlight.js

    const lines = str.trim().split('\n');
    const groups = [];
    let input;
    lines.forEach((line) => {
      if (input) {
        input.push(line);
        if (line[line.length - 1] !== '\\') {
          input = null;
        }
      } else if (line.startsWith('$ ')) {
        const lines = [line.substr(2)];
        groups.push({type: 'input', lines});
        if (line[line.length - 1] === '\\') {
          input = lines;
        }
      } else {
        const type = line[0] === '#' ? 'comment': 'output';
        groups.push({type, lines: [line]});
      }
    });

    const result = groups.map(({type, lines}) => {
      if (type === 'comment') {
        return `<span class="hljs-section">${escapeHtml(lines.join('\n'))}</span>`;
      } else if (type === 'input') {
        return `<strong>$ </strong><em>${escapeHtml(lines.join('\n'))}</span>`;
      } else {
        return `<span>${escapeHtml(lines.join('\n'))}</span>`;
      }
    });

    return result.join('\n');