roadmap/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) => {
    window.location.href = BASE_URL + `${id}#:~:text=${encodeURIComponent(term)}`
  }

  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()
  })
})()