hugo-academic/assets/js/academic-search.js

/*************************************************
 *  Academic
 *  https://github.com/gcushen/hugo-academic
 *
 *  In-built Fuse based search algorithm.
 **************************************************/

/* ---------------------------------------------------------------------------
* Configuration.
* --------------------------------------------------------------------------- */

// Configure Fuse.
let fuseOptions = {
  shouldSort: true,
  includeMatches: true,
  tokenize: true,
  threshold: 0.0,
  location: 0,
  distance: 100,
  maxPatternLength: 32,
  minMatchCharLength: 2,
  keys: [
    {name:'title', weight:0.8},
    {name:'summary', weight:0.6},
    {name:'content', weight:0.5},
    {name:'tags', weight:0.3}
  ]
};

// Configure summary.
let summaryLength = 60;

/* ---------------------------------------------------------------------------
* Functions.
* --------------------------------------------------------------------------- */

// Get query from URI.
function getSearchQuery(name) {
  return decodeURIComponent((location.search.split(name + '=')[1] || '').split('&')[0]).replace(/\+/g, ' ');
}

// Set query in URI without reloading the page.
function updateURL(url) {
  if (history.pushState) {
    window.history.pushState({path:url}, '', url);
  }
}

// Pre-process new search query.
function initSearch(force, fuse) {
  let query = $("#search-query").val();

  // If query deleted, clear results.
  if ( query.length < 1) {
    $('#search-hits').empty();
  }

  // Check for timer event (enter key not pressed) and query less than minimum length required.
  if (!force && query.length < fuseOptions.minMatchCharLength)
    return;

  // Do search.
  $('#search-hits').empty();
  searchAcademic(query, fuse);
  let newURL = window.location.protocol + "//" + window.location.host + window.location.pathname + '?q=' + encodeURIComponent(query) + window.location.hash;
  updateURL(newURL);
}

// Perform search.
function searchAcademic(query, fuse) {
  let results = fuse.search(query);
  // console.log({"results": results});

  if (results.length > 0) {
    $('#search-hits').append('<h3 class="mt-0">' + results.length + ' ' + i18n.results + '</h3>');
    parseResults(query, results);
  } else {
    $('#search-hits').append('<div class="search-no-results">' + i18n.no_results + '</div>');
  }
}

// Parse search results.
function parseResults(query, results) {
  $.each( results, function(key, value) {
    let content = value.item.content;
    let snippet = "";
    let snippetHighlights = [];

    if ( fuseOptions.tokenize ) {
      snippetHighlights.push(query);
    } else {
      $.each( value.matches, function(matchKey, matchValue) {
        if (matchValue.key == "content") {
          let start = (matchValue.indices[0][0]-summaryLength>0) ? matchValue.indices[0][0]-summaryLength : 0;
          let end = (matchValue.indices[0][1]+summaryLength<content.length) ? matchValue.indices[0][1]+summaryLength : content.length;
          snippet += content.substring(start, end);
          snippetHighlights.push(matchValue.value.substring(matchValue.indices[0][0], matchValue.indices[0][1]-matchValue.indices[0][0]+1));
        }
      });
    }

    if (snippet.length < 1) {
      snippet += content.substring(0, summaryLength*2);
    }

    // Load template.
    var template = $('#search-hit-fuse-template').html();

    // Localize content types.
    let content_key = value.item.section;
    if (content_key in content_type) {
      content_key = content_type[content_key];
    }

    // Parse template.
    let templateData = {
      key: key,
      title: value.item.title,
      type: content_key,
      relpermalink: value.item.relpermalink,
      snippet: snippet
    };
    let output = render(template, templateData);
    $('#search-hits').append(output);

    // Highlight search terms in result.
    $.each( snippetHighlights, function(hlKey, hlValue){
      $("#summary-"+key).mark(hlValue);
    });

  });
}

function render(template, data) {
  // Replace placeholders with their values.
  let key, find, re;
  for (key in data) {
    find = '\\{\\{\\s*' + key + '\\s*\\}\\}';  // Expect placeholder in the form `{{x}}`.
    re = new RegExp(find, 'g');
    template = template.replace(re, data[key]);
  }
  return template;
}

/* ---------------------------------------------------------------------------
* Initialize.
* --------------------------------------------------------------------------- */

// If Academic's in-built search is enabled and Fuse loaded, then initialize it.
if (typeof Fuse === 'function') {
// Wait for Fuse to initialize.
  $.getJSON(search_index_filename, function (search_index) {
    let fuse = new Fuse(search_index, fuseOptions);

    // On page load, check for search query in URL.
    if (query = getSearchQuery('q')) {
      $("body").addClass('searching');
      $('.search-results').css({opacity: 0, visibility: "visible"}).animate({opacity: 1},200);
      $("#search-query").val(query);
      $("#search-query").focus();
      initSearch(true, fuse);
    }

    // On search box key up, process query.
    $('#search-query').keyup(function (e) {
      clearTimeout($.data(this, 'searchTimer')); // Ensure only one timer runs!
      if (e.keyCode == 13) {
        initSearch(true, fuse);
      } else {
        $(this).data('searchTimer', setTimeout(function () {
          initSearch(false, fuse);
        }, 250));
      }
    });
  });
}