How to implement search in Hugo

Update config.toml file. Add this snippet to your config.toml file to instruct Hugo to create the index file in JSON format. (RSS and HTML are default outputs, what’s important is to add JSON.

[outputs]
  home = ["HTML", "RSS", "JSON"]

Create layouts/_default/index.json file

Add the following index.json template to specified folder.

{{- $.Scratch.Add "index" slice -}}
{{- range .Site.RegularPages -}}
    {{- $.Scratch.Add "index" (dict "title" .Title "tags" .Params.tags "categories" .Params.categories "contents" .Plain "permalink" .Permalink) -}}
{{- end -}}
{{- $.Scratch.Get "index" | jsonify -}}

Create static/js/search.js file

This file uses jquery, fuse.js, mark.js to search the hugo created index, and return matching content, with highlighting.

summaryInclude=60;
var fuseOptions = {
  shouldSort: true,
  includeMatches: true,
  threshold: 0.0,
  tokenize:true,
  location: 0,
  distance: 100,
  maxPatternLength: 32,
  minMatchCharLength: 1,
  keys: [
    {name:"title",weight:0.8},
    {name:"contents",weight:0.5},
    {name:"tags",weight:0.3},
    {name:"categories",weight:0.3}
  ]
};

var searchQuery = param("s");
if(searchQuery){
  $("#search-query").val(searchQuery);
  executeSearch(searchQuery);
}else {
  $('#search-results').append("<p>Please enter a word or phrase above</p>");
}

function executeSearch(searchQuery){
  $.getJSON( "/index.json", function( data ) {
    var pages = data;
    var fuse = new Fuse(pages, fuseOptions);
    var result = fuse.search(searchQuery);
    console.log({"matches":result});
    if(result.length > 0){
      populateResults(result);
    }else{
      $('#search-results').append("<p>No matches found</p>");
    }
  });
}

function populateResults(result){
  $.each(result,function(key,value){
    var contents= value.item.contents;
    var snippet = "";
    var snippetHighlights=[];
    var tags =[];
    if( fuseOptions.tokenize ){
      snippetHighlights.push(searchQuery);
    }else{
      $.each(value.matches,function(matchKey,mvalue){
        if(mvalue.key == "tags" || mvalue.key == "categories" ){
          snippetHighlights.push(mvalue.value);
        }else if(mvalue.key == "contents"){
          start = mvalue.indices[0][0]-summaryInclude>0?mvalue.indices[0][0]-summaryInclude:0;
          end = mvalue.indices[0][1]+summaryInclude<contents.length?mvalue.indices[0][1]+summaryInclude:contents.length;
          snippet += contents.substring(start,end);
          snippetHighlights.push(mvalue.value.substring(mvalue.indices[0][0],mvalue.indices[0][1]-mvalue.indices[0][0]+1));
        }
      });
    }

    if(snippet.length<1){
      snippet += contents.substring(0,summaryInclude*2);
    }
    //pull template from hugo templarte definition
    var templateDefinition = $('#search-result-template').html();
    //replace values
    var output = render(templateDefinition,{key:key,title:value.item.title,link:value.item.permalink,tags:value.item.tags,categories:value.item.categories,snippet:snippet});
    $('#search-results').append(output);

    $.each(snippetHighlights,function(snipkey,snipvalue){
      $("#summary-"+key).mark(snipvalue);
    });

  });
}

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

function render(templateString, data) {
  var conditionalMatches,conditionalPattern,copy;
  conditionalPattern = /\$\{\s*isset ([a-zA-Z]*) \s*\}(.*)\$\{\s*end\s*}/g;
  //since loop below depends on re.lastInxdex, we use a copy to capture any manipulations whilst inside the loop
  copy = templateString;
  while ((conditionalMatches = conditionalPattern.exec(templateString)) !== null) {
    if(data[conditionalMatches[1]]){
      //valid key, remove conditionals, leave contents.
      copy = copy.replace(conditionalMatches[0],conditionalMatches[2]);
    }else{
      //not valid, remove entire section
      copy = copy.replace(conditionalMatches[0],'');
    }
  }
  templateString = copy;
  //now any conditionals removed we can do simple substitution
  var key, find, re;
  for (key in data) {
    find = '\\$\\{\\s*' + key + '\\s*\\}';
    re = new RegExp(find, 'g');
    templateString = templateString.replace(re, data[key]);
  }
  return templateString;
}

Create content/search.md file

---
title: "Search Results"
sitemap:
  priority : 0.1
layout: "search"
---

Nothing on this page will be visible. This file exists solely to respond to /search URL.

Setting a very low sitemap priority will tell search engines this is not important content.

Create layouts/_default/search.html file

{{ define "footerfiles" }}
<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/fuse.js/3.2.0/fuse.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/mark.js/8.11.1/jquery.mark.min.js"></script>
<script src="{{ "js/search.js" | absURL }}"></script>
{{ end }}
{{ define "main" }}
<section class="resume-section p-3 p-lg-5 d-flex flex-column">
  <div class="my-auto" >
    <form action="{{ "search" | absURL }}">
      <input id="search-query" name="s"/>
    </form>
    <div id="search-results">
     <h3>Matching pages</h3>
    </div>
  </div>
</section>
<!-- this template is sucked in by search.js and appended to the search-results div above. So editing here will adjust style -->
<script id="search-result-template" type="text/x-js-template">
    <div id="summary-${key}">
      <h4><a href="${link}">${title}</a></h4>
      <p>${snippet}</p>
      ${ isset tags }<p>Tags: ${tags}</p>${ end }
      ${ isset categories }<p>Categories: ${categories}</p>${ end }
    </div>
</script>
{{ end }}

Source: gist.github.com/eddiewebb