wiki/assets/js/search.js

// code from https://github.com/danestves/markdown-to-text
const removeMarkdown = (
  markdown,
  options = {
    listUnicodeChar: false,
    stripListLeaders: true,
    gfm: true,
    useImgAltText: false,
    preserveLinks: false,
  }
) => {
  let output = markdown || '';
  output = output.replace(/^(-\s*?|\*\s*?|_\s*?){3,}\s*$/gm, '');

  try {
    if (options.stripListLeaders) {
      if (options.listUnicodeChar)
        output = output.replace(
          /^([\s\t]*)([\*\-\+]|\d+\.)\s+/gm,
          options.listUnicodeChar + ' $1'
        );
      else output = output.replace(/^([\s\t]*)([\*\-\+]|\d+\.)\s+/gm, '$1');
    }
    if (options.gfm) {
      output = output
        .replace(/\n={2,}/g, '\n')
        .replace(/~{3}.*\n/g, '')
        .replace(/~~/g, '')
        .replace(/`{3}.*\n/g, '');
    }
    if (options.preserveLinks) {
      output = output.replace(/\[(.*?)\][\[\(](.*?)[\]\)]/g, '$1 ($2)');
    }
    output = output
      .replace(/<[^>]*>/g, '')
      .replace(/^[=\-]{2,}\s*$/g, '')
      .replace(/\[\^.+?\](\: .*?$)?/g, '')
      .replace(/\s{0,2}\[.*?\]: .*?$/g, '')
      .replace(/\!\[(.*?)\][\[\(].*?[\]\)]/g, options.useImgAltText ? '$1' : '')
      .replace(/\[(.*?)\][\[\(].*?[\]\)]/g, '$1')
      .replace(/^\s{0,3}>\s?/g, '')
      .replace(/(^|\n)\s{0,3}>\s?/g, '\n\n')
      .replace(/^\s{1,2}\[(.*?)\]: (\S+)( ".*?")?\s*$/g, '')
      .replace(
        /^(\n)?\s{0,}#{1,6}\s+| {0,}(\n)?\s{0,}#{0,} {0,}(\n)?\s{0,}$/gm,
        '$1$2$3'
      )
      .replace(/([\*_]{1,3})(\S.*?\S{0,1})\1/g, '$2')
      .replace(/([\*_]{1,3})(\S.*?\S{0,1})\1/g, '$2')
      .replace(/(`{3,})(.*?)\1/gm, '$2')
      .replace(/`(.+?)`/g, '$1')
      .replace(/\n{2,}/g, '\n\n');
  } catch (e) {
    console.error(e);
    return markdown;
  }
  return output;
};
// -----

(async function () {
  const encoder = (str) => str.toLowerCase().split(/([^a-z]|[^\x00-\x7F])+/);
  const contentIndex = new FlexSearch.Document({
    cache: true,
    charset: 'latin:extra',
    optimize: true,
    index: [
      {
        field: 'content',
        tokenize: 'reverse',
        encode: encoder,
      },
      {
        field: 'title',
        tokenize: 'forward',
        encode: encoder,
      },
    ],
  });

  const { content } = await fetchData;
  for (const [key, value] of Object.entries(content)) {
    contentIndex.add({
      id: key,
      title: value.title,
      content: removeMarkdown(value.content),
    });
  }

  const highlight = (content, term) => {
    const highlightWindow = 20;
    const tokenizedTerm = term.split(/\s+/).filter((t) => t !== '');
    const splitText = content.split(/\s+/).filter((t) => t !== '');
    const includesCheck = (token) =>
      tokenizedTerm.some((term) =>
        token.toLowerCase().startsWith(term.toLowerCase())
      );

    const occurrencesIndices = splitText.map(includesCheck);

    // calculate best index
    let bestSum = 0;
    let bestIndex = 0;
    for (
      let i = 0;
      i < Math.max(occurrencesIndices.length - highlightWindow, 0);
      i++
    ) {
      const window = occurrencesIndices.slice(i, i + highlightWindow);
      const windowSum = window.reduce((total, cur) => total + cur, 0);
      if (windowSum >= bestSum) {
        bestSum = windowSum;
        bestIndex = i;
      }
    }

    const startIndex = Math.max(bestIndex - highlightWindow, 0);
    const endIndex = Math.min(
      startIndex + 2 * highlightWindow,
      splitText.length
    );
    const mappedText = splitText
      .slice(startIndex, endIndex)
      .map((token) => {
        if (includesCheck(token)) {
          return `<span class="search-highlight">${token}</span>`;
        }
        return token;
      })
      .join(' ')
      .replaceAll('</span> <span class="search-highlight">', ' ');
    return `${startIndex === 0 ? '' : '...'}${mappedText}${
      endIndex === splitText.length ? '' : '...'
    }`;
  };

  const resultToHTML = ({ url, title, content, term }) => {
    const text = removeMarkdown(content);
    const resultTitle = highlight(title, term);
    const resultText = highlight(text, term);
    return `<button class="result-card" id="${url}">
        <h3>${resultTitle}</h3>
        <p>${resultText}</p>
    </button>`;
  };

  const redir = (id, term) => {
    // SPA navigation
    window.navigate(
      new URL(
        `${BASE_URL.slice(0, -1)}${id}#:~:text=${encodeURIComponent(term)}/`
      ),
      '.singlePage'
    );
    closeSearch();
  };

  const formatForDisplay = (id) => ({
    id,
    url: id,
    title: content[id].title,
    content: content[id].content,
  });

  const source = document.getElementById('search-bar');
  const results = document.getElementById('results-container');
  let term;
  source.addEventListener('keyup', (e) => {
    if (e.key === 'Enter') {
      const anchor = document.getElementsByClassName('result-card')[0];
      redir(anchor.id, term);
    }
  });
  source.addEventListener('input', (e) => {
    term = e.target.value;
    const searchResults = contentIndex.search(term, [
      {
        field: 'content',
        limit: 10,
      },
      {
        field: 'title',
        limit: 5,
      },
    ]);
    const getByField = (field) => {
      const results = searchResults.filter((x) => x.field === field);
      if (results.length === 0) {
        return [];
      } else {
        return [...results[0].result];
      }
    };
    const allIds = new Set([...getByField('title'), ...getByField('content')]);
    const finalResults = [...allIds].map(formatForDisplay);

    // display
    if (finalResults.length === 0) {
      results.innerHTML = `<button class="result-card">
                    <h3>No results.</h3>
                    <p>Try another search term?</p>
                </button>`;
    } else {
      results.innerHTML = finalResults
        .map((result) =>
          resultToHTML({
            ...result,
            term,
          })
        )
        .join('\n');
      const anchors = document.getElementsByClassName('result-card');
      [...anchors].forEach((anchor) => {
        anchor.onclick = () => redir(anchor.id, term);
      });
    }
  });

  const searchContainer = document.getElementById('search-container');

  function openSearch() {
    if (
      searchContainer.style.display === 'none' ||
      searchContainer.style.display === ''
    ) {
      source.value = '';
      results.innerHTML = '';
      searchContainer.style.display = 'block';
      source.focus();
    } else {
      searchContainer.style.display = 'none';
    }
  }

  function closeSearch() {
    searchContainer.style.display = 'none';
  }

  document.addEventListener('keydown', (event) => {
    if (event.key === 'k' && (event.ctrlKey || event.metaKey)) {
      event.preventDefault();
      openSearch();
    }
    if (event.key === 'Escape') {
      event.preventDefault();
      closeSearch();
    }
  });

  const searchButton = document.getElementById('search-icon');
  searchButton.addEventListener('click', (evt) => {
    openSearch();
  });
  searchButton.addEventListener('keydown', (evt) => {
    openSearch();
  });
  searchContainer.addEventListener('click', (evt) => {
    closeSearch();
  });
  document.getElementById('search-space').addEventListener('click', (evt) => {
    evt.stopPropagation();
  });
})();