WIP: Implementing search

4 files changed, 354 insertions, 3 deletions

diff --git a/assets/js/search.js b/assets/js/search.js
new file mode 100644
index 0000000..c261586
--- /dev/null
+++ b/assets/js/search.js
@@ -0,0 +1,311 @@
+'use strict';
+
+let pagesIndex, searchIndex;
+
+// Maximum length (in words) of each text blurb. You can change this
+// value if you find that 100 is too short or too long for your taste.
+const MAX_SUMMARY_LENGTH = 100;
+
+// Since the blurb is comprised of full sentences containing any search
+// term, we need a way to identify where each sentence begins/ends. This
+// regex will be used to produce a list of all sentences from the page
+// content.
+const SENTENCE_BOUNDARY_REGEX = /\b\.\s/gm;
+
+// This is a simple regex that produces a list of words from the text
+// it is applied to. This will be used to check the number of total words
+// in the blurb as it is being built.
+const WORD_REGEX = /\b(\w*)[\W|\s|\b]?/gm;
+
+async function initSearchIndex() {
+  try {
+    const response = await fetch('/index.json');
+    pagesIndex = await response.json();
+    searchIndex = lunr(function () {
+      this.field('title');
+      this.field('categories');
+      this.field('tags');
+      this.field('content');
+      this.ref('href');
+
+      pagesIndex.forEach((page) => this.add(page));
+    });
+  } catch (e) {
+    console.log(e); // eslint-disable-line no-console
+  }
+}
+
+function handleSearchQuery(event) {
+  event.preventDefault();
+
+  const query = $('#search').val().trim().toLowerCase();
+  if (!query) {
+    displayErrorMessage('Please enter a search term.');
+    return;
+  }
+
+  const results = searchSite(query);
+  if (!results.length) {
+    displayErrorMessage('No results found.');
+    return;
+  }
+
+  hideErrorMessage();
+  renderSearchResults(query, results);
+}
+
+function searchSite(query) {
+  const originalQuery = query;
+  query = getLunrSearchQuery(query);
+  let results = getSearchResults(query);
+
+  if (results.length > 0) {
+    return results;
+  }
+
+  if (query !== originalQuery) {
+    return getSearchResults(originalQuery);
+  }
+
+  return [];
+}
+
+function getSearchResults(query) {
+  return searchIndex.search(query).flatMap((hit) => {
+    if (hit.ref === 'undefined') return [];
+    let pageMatch = pagesIndex.filter((page) => page.href === hit.ref)[0];
+    pageMatch.score = hit.score;
+    return [pageMatch];
+  });
+}
+
+function getLunrSearchQuery(query) {
+  const searchTerms = query.split(' ');
+  if (searchTerms.length === 1) {
+    return query;
+  }
+  query = '';
+  for (const term of searchTerms) {
+    query += `+${term} `;
+  }
+  return query.trim();
+}
+
+function displayErrorMessage(message) {
+  $('.search-container').addClass('form-item-error');
+  $('.search-error-message').html(message);
+  $('.search-container').removeClass('focused');
+  $('.search-error').removeClass('hide-element');
+}
+
+function hideErrorMessage() {
+  $('.search-container').removeClass('form-item-error');
+  $('.search-error-message').empty();
+  $('.search-container').addClass('focused');
+  $('.search-error').addClass('hide-element');
+}
+
+function handleClearSearchButtonClicked() {
+  hideSearchResults();
+  hideErrorMessage();
+  clearSearchResults();
+  clearAndFocusSearchInput();
+}
+
+function hideSearchResults() {
+  $('#clear-search-results').addClass('hide-element');
+  $('#site-search').removeClass('expanded');
+  $('#search-results').addClass('hide-element');
+}
+
+function renderSearchResults(query, results) {
+  clearSearchResults();
+  updateSearchResults(query, results);
+  showSearchResults();
+  scrollToTop();
+}
+
+function clearSearchResults() {
+  $('#query').empty();
+  $('#search-results-body').empty();
+  $('#results-count').empty();
+  $('#results-count-text').empty();
+}
+
+function clearAndFocusSearchInput() {
+  $('.search-form-input').val('').focus();
+}
+
+function updateSearchResults(query, results) {
+  $('#query').html(query);
+  $('#search-results-body').html(results.map((hit) => `
+  <article class="post" data-score="${hit.score.toFixed(2)}">
+    <header>
+      <h2 class="post-title">
+      <a href="${hit.href}?utm_source=search" class="search-result-page-title">${hit.title}</a>
+      </h2>
+    </header>
+    <p class="post-content">${createSearchResultBlurb(query, hit.content)}</p>
+  </article>
+  `
+  ).join(''));
+
+  const searchResultListItems = $('#search-results-body article');
+  $('#results-count').html(searchResultListItems.length);
+  $('#results-count-text').html(searchResultListItems.length > 1 ? 'results' : 'result');
+}
+
+function createSearchResultBlurb(query, pageContent) {
+  const searchQueryRegex = new RegExp(createQueryStringRegex(query), 'gmi');
+  const searchQueryHits = Array.from(
+    pageContent.matchAll(searchQueryRegex),
+    (m) => m.index
+  );
+  const sentenceBoundaries = Array.from(
+    pageContent.matchAll(SENTENCE_BOUNDARY_REGEX),
+    (m) => m.index
+  );
+  let parsedSentence = '';
+  let searchResultText = '';
+  let lastEndOfSentence = 0;
+  for (const hitLocation of searchQueryHits) {
+    if (hitLocation > lastEndOfSentence) {
+      for (let i = 0; i < sentenceBoundaries.length; i++) {
+        if (sentenceBoundaries[i] > hitLocation) {
+          const startOfSentence = i > 0 ? sentenceBoundaries[i - 1] + 1 : 0;
+          const endOfSentence = sentenceBoundaries[i];
+          lastEndOfSentence = endOfSentence;
+          parsedSentence = pageContent.slice(startOfSentence, endOfSentence).trim();
+          searchResultText += `${parsedSentence} ... `;
+          break;
+        }
+      }
+    }
+    const searchResultWords = tokenize(searchResultText);
+    const pageBreakers = searchResultWords.filter((word) => word.length > 50);
+    if (pageBreakers.length > 0) {
+      searchResultText = fixPageBreakers(searchResultText, pageBreakers);
+    }
+    if (searchResultWords.length >= MAX_SUMMARY_LENGTH) break;
+  }
+  return ellipsize(searchResultText, MAX_SUMMARY_LENGTH).replace(
+    searchQueryRegex,
+    '<span class="search-item">$&</span>'
+  );
+}
+
+function createQueryStringRegex(query) {
+  const searchTerms = query.split(' ');
+  if (searchTerms.length === 1) {
+    return query;
+  }
+  query = '';
+  for (const term of searchTerms) {
+    query += `${term}|`;
+  }
+  query = query.slice(0, -1);
+  return `(${query})`;
+}
+
+function tokenize(input) {
+  const wordMatches = Array.from(input.matchAll(WORD_REGEX), (m) => m);
+  return wordMatches.map((m) => ({
+    word: m[0],
+    start: m.index,
+    end: m.index + m[0].length,
+    length: m[0].length
+  }));
+}
+
+function fixPageBreakers(input, largeWords) {
+  largeWords.forEach((word) => {
+    const chunked = chunkify(word.word, 20);
+    input = input.replace(word.word, chunked);
+  });
+  return input;
+}
+
+function chunkify(input, chunkSize) {
+  let output = '';
+  let totalChunks = (input.length / chunkSize) | 0;
+  let lastChunkIsUneven = input.length % chunkSize > 0;
+  if (lastChunkIsUneven) {
+    totalChunks += 1;
+  }
+  for (let i = 0; i < totalChunks; i++) {
+    let start = i * chunkSize;
+    let end = start + chunkSize;
+    if (lastChunkIsUneven && i === totalChunks - 1) {
+      end = input.length;
+    }
+    output += input.slice(start, end) + " ";
+  }
+  return output;
+}
+
+function showSearchResults() {
+  $('#search-results').removeClass('hide-element');
+  $('#site-search').removeClass('expanded');
+  $('#clear-search-results').removeClass('hide-element');
+}
+
+function scrollToTop() {
+  const toTopInterval = setInterval(function () {
+    const supportedScrollTop = document.body.scrollTop > 0 ? document.body : document.documentElement;
+    if (supportedScrollTop.scrollTop > 0) {
+      supportedScrollTop.scrollTop = supportedScrollTop.scrollTop - 50;
+    }
+    if (supportedScrollTop.scrollTop < 1) {
+      clearInterval(toTopInterval);
+    }
+  }, 10);
+}
+
+function ellipsize(input, maxLength) {
+  const words = tokenize(input);
+  if (words.length <= maxLength) {
+    return input;
+  }
+  return input.slice(0, words[maxLength].end) + "...";
+}
+
+if (!String.prototype.matchAll) {
+  String.prototype.matchAll = function (regex) {
+    "use strict";
+    function ensureFlag(flags, flag) {
+      return flags.includes(flag) ? flags : flags + flag;
+    }
+    function* matchAll(str, regex) {
+      const localCopy = new RegExp(regex, ensureFlag(regex.flags, "g"));
+      let match;
+      while ((match = localCopy.exec(str))) {
+        match.index = localCopy.lastIndex - match[0].length;
+        yield match;
+      }
+    }
+    return matchAll(this, regex);
+  };
+}
+
+$(function() {
+  const searchForm = $('#search-form');
+  const searchInput = $('#search');
+
+  if (searchForm.length === 0 || searchInput.length === 0) {
+    return;
+  }
+
+  initSearchIndex();
+
+  searchForm.submit((e) => {
+    e.preventDefault();
+  });
+
+  searchInput.on('keypress', (e) => {
+    if (e.which === 13) {
+      handleSearchQuery(e);
+    }
+  });
+
+  $('#clear-search-results').on('click', () => handleClearSearchButtonClicked());
+});
diff --git a/assets/js/vendor/lunr.min.js b/assets/js/vendor/lunr.min.js
new file mode 100644
index 0000000..cdc94cd
--- /dev/null
+++ b/assets/js/vendor/lunr.min.js
@@ -0,0 +1,6 @@
+/**
+ * lunr - http://lunrjs.com - A bit like Solr, but much smaller and not as bright - 2.3.9
+ * Copyright (C) 2020 Oliver Nightingale
+ * @license MIT
+ */
+!function(){var e=function(t){var r=new e.Builder;return r.pipeline.add(e.trimmer,e.stopWordFilter,e.stemmer),r.searchPipeline.add(e.stemmer),t.call(r,r),r.build()};e.version="2.3.9",e.utils={},e.utils.warn=function(e){return function(t){e.console&&console.warn&&console.warn(t)}}(this),e.utils.asString=function(e){return void 0===e||null===e?"":e.toString()},e.utils.clone=function(e){if(null===e||void 0===e)return e;for(var t=Object.create(null),r=Object.keys(e),i=0;i<r.length;i++){var n=r[i],s=e[n];if(Array.isArray(s))t[n]=s.slice();else{if("string"!=typeof s&&"number"!=typeof s&&"boolean"!=typeof s)throw new TypeError("clone is not deep and does not support nested objects");t[n]=s}}return t},e.FieldRef=function(e,t,r){this.docRef=e,this.fieldName=t,this._stringValue=r},e.FieldRef.joiner="/",e.FieldRef.fromString=function(t){var r=t.indexOf(e.FieldRef.joiner);if(r===-1)throw"malformed field ref string";var i=t.slice(0,r),n=t.slice(r+1);return new e.FieldRef(n,i,t)},e.FieldRef.prototype.toString=function(){return void 0==this._stringValue&&(this._stringValue=this.fieldName+e.FieldRef.joiner+this.docRef),this._stringValue},e.Set=function(e){if(this.elements=Object.create(null),e){this.length=e.length;for(var t=0;t<this.length;t++)this.elements[e[t]]=!0}else this.length=0},e.Set.complete={intersect:function(e){return e},union:function(){return this},contains:function(){return!0}},e.Set.empty={intersect:function(){return this},union:function(e){return e},contains:function(){return!1}},e.Set.prototype.contains=function(e){return!!this.elements[e]},e.Set.prototype.intersect=function(t){var r,i,n,s=[];if(t===e.Set.complete)return this;if(t===e.Set.empty)return t;this.length<t.length?(r=this,i=t):(r=t,i=this),n=Object.keys(r.elements);for(var o=0;o<n.length;o++){var a=n[o];a in i.elements&&s.push(a)}return new e.Set(s)},e.Set.prototype.union=function(t){return t===e.Set.complete?e.Set.complete:t===e.Set.empty?this:new e.Set(Object.keys(this.elements).concat(Object.keys(t.elements)))},e.idf=function(e,t){var r=0;for(var i in e)"_index"!=i&&(r+=Object.keys(e[i]).length);var n=(t-r+.5)/(r+.5);return Math.log(1+Math.abs(n))},e.Token=function(e,t){this.str=e||"",this.metadata=t||{}},e.Token.prototype.toString=function(){return this.str},e.Token.prototype.update=function(e){return this.str=e(this.str,this.metadata),this},e.Token.prototype.clone=function(t){return t=t||function(e){return e},new e.Token(t(this.str,this.metadata),this.metadata)},e.tokenizer=function(t,r){if(null==t||void 0==t)return[];if(Array.isArray(t))return t.map(function(t){return new e.Token(e.utils.asString(t).toLowerCase(),e.utils.clone(r))});for(var i=t.toString().toLowerCase(),n=i.length,s=[],o=0,a=0;o<=n;o++){var u=i.charAt(o),l=o-a;if(u.match(e.tokenizer.separator)||o==n){if(l>0){var c=e.utils.clone(r)||{};c.position=[a,l],c.index=s.length,s.push(new e.Token(i.slice(a,o),c))}a=o+1}}return s},e.tokenizer.separator=/[\s\-]+/,e.Pipeline=function(){this._stack=[]},e.Pipeline.registeredFunctions=Object.create(null),e.Pipeline.registerFunction=function(t,r){r in this.registeredFunctions&&e.utils.warn("Overwriting existing registered function: "+r),t.label=r,e.Pipeline.registeredFunctions[t.label]=t},e.Pipeline.warnIfFunctionNotRegistered=function(t){var r=t.label&&t.label in this.registeredFunctions;r||e.utils.warn("Function is not registered with pipeline. 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e}},e.stopWordFilter=e.generateStopWordFilter(["a","able","about","across","after","all","almost","also","am","among","an","and","any","are","as","at","be","because","been","but","by","can","cannot","could","dear","did","do","does","either","else","ever","every","for","from","get","got","had","has","have","he","her","hers","him","his","how","however","i","if","in","into","is","it","its","just","least","let","like","likely","may","me","might","most","must","my","neither","no","nor","not","of","off","often","on","only","or","other","our","own","rather","said","say","says","she","should","since","so","some","than","that","the","their","them","then","there","these","they","this","tis","to","too","twas","us","wants","was","we","were","what","when","where","which","while","who","whom","why","will","with","would","yet","you","your"]),e.Pipeline.registerFunction(e.stopWordFilter,"stopWordFilter"),e.trimmer=function(e){return e.update(function(e){return e.replace(/^\W+/,"").replace(/\W+$/,"")})},e.Pipeline.registerFunction(e.trimmer,"trimmer"),e.TokenSet=function(){this["final"]=!1,this.edges={},this.id=e.TokenSet._nextId,e.TokenSet._nextId+=1},e.TokenSet._nextId=1,e.TokenSet.fromArray=function(t){for(var r=new e.TokenSet.Builder,i=0,n=t.length;i<n;i++)r.insert(t[i]);return r.finish(),r.root},e.TokenSet.fromClause=function(t){return"editDistance"in t?e.TokenSet.fromFuzzyString(t.term,t.editDistance):e.TokenSet.fromString(t.term)},e.TokenSet.fromFuzzyString=function(t,r){for(var i=new e.TokenSet,n=[{node:i,editsRemaining:r,str:t}];n.length;){var s=n.pop();if(s.str.length>0){var o,a=s.str.charAt(0);a in s.node.edges?o=s.node.edges[a]:(o=new e.TokenSet,s.node.edges[a]=o),1==s.str.length&&(o["final"]=!0),n.push({node:o,editsRemaining:s.editsRemaining,str:s.str.slice(1)})}if(0!=s.editsRemaining){if("*"in s.node.edges)var u=s.node.edges["*"];else{var u=new e.TokenSet;s.node.edges["*"]=u}if(0==s.str.length&&(u["final"]=!0),n.push({node:u,editsRemaining:s.editsRemaining-1,str:s.str}),s.str.length>1&&n.push({node:s.node,editsRemaining:s.editsRemaining-1,str:s.str.slice(1)}),1==s.str.length&&(s.node["final"]=!0),s.str.length>=1){if("*"in s.node.edges)var l=s.node.edges["*"];else{var l=new e.TokenSet;s.node.edges["*"]=l}1==s.str.length&&(l["final"]=!0),n.push({node:l,editsRemaining:s.editsRemaining-1,str:s.str.slice(1)})}if(s.str.length>1){var c,h=s.str.charAt(0),d=s.str.charAt(1);d in s.node.edges?c=s.node.edges[d]:(c=new e.TokenSet,s.node.edges[d]=c),1==s.str.length&&(c["final"]=!0),n.push({node:c,editsRemaining:s.editsRemaining-1,str:h+s.str.slice(2)})}}}return i},e.TokenSet.fromString=function(t){for(var r=new e.TokenSet,i=r,n=0,s=t.length;n<s;n++){var o=t[n],a=n==s-1;if("*"==o)r.edges[o]=r,r["final"]=a;else{var u=new e.TokenSet;u["final"]=a,r.edges[o]=u,r=u}}return i},e.TokenSet.prototype.toArray=function(){for(var e=[],t=[{prefix:"",node:this}];t.length;){var r=t.pop(),i=Object.keys(r.node.edges),n=i.length;r.node["final"]&&(r.prefix.charAt(0),e.push(r.prefix));for(var s=0;s<n;s++){var o=i[s];t.push({prefix:r.prefix.concat(o),node:r.node.edges[o]})}}return e},e.TokenSet.prototype.toString=function(){if(this._str)return this._str;for(var e=this["final"]?"1":"0",t=Object.keys(this.edges).sort(),r=t.length,i=0;i<r;i++){var n=t[i],s=this.edges[n];e=e+n+s.id}return e},e.TokenSet.prototype.intersect=function(t){for(var r=new e.TokenSet,i=void 0,n=[{qNode:t,output:r,node:this}];n.length;){i=n.pop();for(var s=Object.keys(i.qNode.edges),o=s.length,a=Object.keys(i.node.edges),u=a.length,l=0;l<o;l++)for(var c=s[l],h=0;h<u;h++){var d=a[h];if(d==c||"*"==c){var f=i.node.edges[d],p=i.qNode.edges[c],y=f["final"]&&p["final"],m=void 0;d in i.output.edges?(m=i.output.edges[d],m["final"]=m["final"]||y):(m=new e.TokenSet,m["final"]=y,i.output.edges[d]=m),n.push({qNode:p,output:m,node:f})}}}return r},e.TokenSet.Builder=function(){this.previousWord="",this.root=new e.TokenSet,this.uncheckedNodes=[],this.minimizedNodes={}},e.TokenSet.Builder.prototype.insert=function(t){var r,i=0;if(t<this.previousWord)throw new Error("Out of order word insertion");for(var n=0;n<t.length&&n<this.previousWord.length&&t[n]==this.previousWord[n];n++)i++;this.minimize(i),r=0==this.uncheckedNodes.length?this.root:this.uncheckedNodes[this.uncheckedNodes.length-1].child;for(var n=i;n<t.length;n++){var s=new e.TokenSet,o=t[n];r.edges[o]=s,this.uncheckedNodes.push({parent:r,"char":o,child:s}),r=s}r["final"]=!0,this.previousWord=t},e.TokenSet.Builder.prototype.finish=function(){this.minimize(0)},e.TokenSet.Builder.prototype.minimize=function(e){for(var t=this.uncheckedNodes.length-1;t>=e;t--){var r=this.uncheckedNodes[t],i=r.child.toString();i in this.minimizedNodes?r.parent.edges[r["char"]]=this.minimizedNodes[i]:(r.child._str=i,this.minimizedNodes[i]=r.child),this.uncheckedNodes.pop()}},e.Index=function(e){this.invertedIndex=e.invertedIndex,this.fieldVectors=e.fieldVectors,this.tokenSet=e.tokenSet,this.fields=e.fields,this.pipeline=e.pipeline},e.Index.prototype.search=function(t){return this.query(function(r){var i=new e.QueryParser(t,r);i.parse()})},e.Index.prototype.query=function(t){for(var r=new e.Query(this.fields),i=Object.create(null),n=Object.create(null),s=Object.create(null),o=Object.create(null),a=Object.create(null),u=0;u<this.fields.length;u++)n[this.fields[u]]=new e.Vector;t.call(r,r);for(var u=0;u<r.clauses.length;u++){var l=r.clauses[u],c=null,h=e.Set.empty;c=l.usePipeline?this.pipeline.runString(l.term,{fields:l.fields}):[l.term];for(var d=0;d<c.length;d++){var f=c[d];l.term=f;var p=e.TokenSet.fromClause(l),y=this.tokenSet.intersect(p).toArray();if(0===y.length&&l.presence===e.Query.presence.REQUIRED){for(var m=0;m<l.fields.length;m++){var v=l.fields[m];o[v]=e.Set.empty}break}for(var g=0;g<y.length;g++)for(var x=y[g],w=this.invertedIndex[x],Q=w._index,m=0;m<l.fields.length;m++){var v=l.fields[m],k=w[v],S=Object.keys(k),E=x+"/"+v,L=new e.Set(S);if(l.presence==e.Query.presence.REQUIRED&&(h=h.union(L),void 0===o[v]&&(o[v]=e.Set.complete)),l.presence!=e.Query.presence.PROHIBITED){if(n[v].upsert(Q,l.boost,function(e,t){return e+t}),!s[E]){for(var b=0;b<S.length;b++){var P,T=S[b],O=new e.FieldRef(T,v),I=k[T];void 0===(P=i[O])?i[O]=new e.MatchData(x,v,I):P.add(x,v,I)}s[E]=!0}}else void 0===a[v]&&(a[v]=e.Set.empty),a[v]=a[v].union(L)}}if(l.presence===e.Query.presence.REQUIRED)for(var m=0;m<l.fields.length;m++){var v=l.fields[m];o[v]=o[v].intersect(h)}}for(var R=e.Set.complete,F=e.Set.empty,u=0;u<this.fields.length;u++){var v=this.fields[u];o[v]&&(R=R.intersect(o[v])),a[v]&&(F=F.union(a[v]))}var C=Object.keys(i),N=[],_=Object.create(null);if(r.isNegated()){C=Object.keys(this.fieldVectors);for(var u=0;u<C.length;u++){var O=C[u],j=e.FieldRef.fromString(O);i[O]=new e.MatchData}}for(var u=0;u<C.length;u++){var j=e.FieldRef.fromString(C[u]),D=j.docRef;if(R.contains(D)&&!F.contains(D)){var A,B=this.fieldVectors[j],V=n[j.fieldName].similarity(B);if(void 0!==(A=_[D]))A.score+=V,A.matchData.combine(i[j]);else{var z={ref:D,score:V,matchData:i[j]};_[D]=z,N.push(z)}}}return N.sort(function(e,t){return t.score-e.score})},e.Index.prototype.toJSON=function(){var t=Object.keys(this.invertedIndex).sort().map(function(e){return[e,this.invertedIndex[e]]},this),r=Object.keys(this.fieldVectors).map(function(e){return[e,this.fieldVectors[e].toJSON()]},this);return{version:e.version,fields:this.fields,fieldVectors:r,invertedIndex:t,pipeline:this.pipeline.toJSON()}},e.Index.load=function(t){var r={},i={},n=t.fieldVectors,s=Object.create(null),o=t.invertedIndex,a=new e.TokenSet.Builder,u=e.Pipeline.load(t.pipeline);t.version!=e.version&&e.utils.warn("Version mismatch when loading serialised index. Current version of lunr '"+e.version+"' does not match serialized index '"+t.version+"'");for(var l=0;l<n.length;l++){var c=n[l],h=c[0],d=c[1];i[h]=new e.Vector(d)}for(var l=0;l<o.length;l++){var c=o[l],f=c[0],p=c[1];a.insert(f),s[f]=p}return a.finish(),r.fields=t.fields,r.fieldVectors=i,r.invertedIndex=s,r.tokenSet=a.root,r.pipeline=u,new e.Index(r)},e.Builder=function(){this._ref="id",this._fields=Object.create(null),this._documents=Object.create(null),this.invertedIndex=Object.create(null),this.fieldTermFrequencies={},this.fieldLengths={},this.tokenizer=e.tokenizer,this.pipeline=new e.Pipeline,this.searchPipeline=new e.Pipeline,this.documentCount=0,this._b=.75,this._k1=1.2,this.termIndex=0,this.metadataWhitelist=[]},e.Builder.prototype.ref=function(e){this._ref=e},e.Builder.prototype.field=function(e,t){if(/\//.test(e))throw new RangeError("Field '"+e+"' contains illegal character '/'");this._fields[e]=t||{}},e.Builder.prototype.b=function(e){e<0?this._b=0:e>1?this._b=1:this._b=e},e.Builder.prototype.k1=function(e){this._k1=e},e.Builder.prototype.add=function(t,r){var i=t[this._ref],n=Object.keys(this._fields);this._documents[i]=r||{},this.documentCount+=1;for(var s=0;s<n.length;s++){var o=n[s],a=this._fields[o].extractor,u=a?a(t):t[o],l=this.tokenizer(u,{fields:[o]}),c=this.pipeline.run(l),h=new e.FieldRef(i,o),d=Object.create(null);this.fieldTermFrequencies[h]=d,this.fieldLengths[h]=0,this.fieldLengths[h]+=c.length;for(var f=0;f<c.length;f++){var p=c[f];if(void 0==d[p]&&(d[p]=0),d[p]+=1,void 0==this.invertedIndex[p]){var y=Object.create(null);y._index=this.termIndex,this.termIndex+=1;for(var m=0;m<n.length;m++)y[n[m]]=Object.create(null);this.invertedIndex[p]=y}void 0==this.invertedIndex[p][o][i]&&(this.invertedIndex[p][o][i]=Object.create(null));for(var v=0;v<this.metadataWhitelist.length;v++){var g=this.metadataWhitelist[v],x=p.metadata[g];void 0==this.invertedIndex[p][o][i][g]&&(this.invertedIndex[p][o][i][g]=[]),this.invertedIndex[p][o][i][g].push(x)}}}},e.Builder.prototype.calculateAverageFieldLengths=function(){for(var t=Object.keys(this.fieldLengths),r=t.length,i={},n={},s=0;s<r;s++){var o=e.FieldRef.fromString(t[s]),a=o.fieldName;n[a]||(n[a]=0),n[a]+=1,i[a]||(i[a]=0),i[a]+=this.fieldLengths[o]}for(var u=Object.keys(this._fields),s=0;s<u.length;s++){var l=u[s];i[l]=i[l]/n[l]}this.averageFieldLength=i},e.Builder.prototype.createFieldVectors=function(){for(var t={},r=Object.keys(this.fieldTermFrequencies),i=r.length,n=Object.create(null),s=0;s<i;s++){for(var o=e.FieldRef.fromString(r[s]),a=o.fieldName,u=this.fieldLengths[o],l=new e.Vector,c=this.fieldTermFrequencies[o],h=Object.keys(c),d=h.length,f=this._fields[a].boost||1,p=this._documents[o.docRef].boost||1,y=0;y<d;y++){var m,v,g,x=h[y],w=c[x],Q=this.invertedIndex[x]._index;void 0===n[x]?(m=e.idf(this.invertedIndex[x],this.documentCount),n[x]=m):m=n[x],v=m*((this._k1+1)*w)/(this._k1*(1-this._b+this._b*(u/this.averageFieldLength[a]))+w),v*=f,v*=p,g=Math.round(1e3*v)/1e3,l.insert(Q,g)}t[o]=l}this.fieldVectors=t},e.Builder.prototype.createTokenSet=function(){this.tokenSet=e.TokenSet.fromArray(Object.keys(this.invertedIndex).sort())},e.Builder.prototype.build=function(){return this.calculateAverageFieldLengths(),this.createFieldVectors(),this.createTokenSet(),new e.Index({invertedIndex:this.invertedIndex,fieldVectors:this.fieldVectors,tokenSet:this.tokenSet,fields:Object.keys(this._fields),pipeline:this.searchPipeline})},e.Builder.prototype.use=function(e){var t=Array.prototype.slice.call(arguments,1);t.unshift(this),e.apply(this,t)},e.MatchData=function(e,t,r){for(var i=Object.create(null),n=Object.keys(r||{}),s=0;s<n.length;s++){var o=n[s];i[o]=r[o].slice()}this.metadata=Object.create(null),void 0!==e&&(this.metadata[e]=Object.create(null),this.metadata[e][t]=i)},e.MatchData.prototype.combine=function(e){for(var t=Object.keys(e.metadata),r=0;r<t.length;r++){var i=t[r],n=Object.keys(e.metadata[i]);void 0==this.metadata[i]&&(this.metadata[i]=Object.create(null));for(var s=0;s<n.length;s++){var o=n[s],a=Object.keys(e.metadata[i][o]);void 0==this.metadata[i][o]&&(this.metadata[i][o]=Object.create(null));for(var u=0;u<a.length;u++){var l=a[u];void 0==this.metadata[i][o][l]?this.metadata[i][o][l]=e.metadata[i][o][l]:this.metadata[i][o][l]=this.metadata[i][o][l].concat(e.metadata[i][o][l])}}}},e.MatchData.prototype.add=function(e,t,r){if(!(e in this.metadata))return this.metadata[e]=Object.create(null),void(this.metadata[e][t]=r);if(!(t in this.metadata[e]))return void(this.metadata[e][t]=r);for(var i=Object.keys(r),n=0;n<i.length;n++){var s=i[n];s in this.metadata[e][t]?this.metadata[e][t][s]=this.metadata[e][t][s].concat(r[s]):this.metadata[e][t][s]=r[s]}},e.Query=function(e){this.clauses=[],this.allFields=e},e.Query.wildcard=new String("*"),e.Query.wildcard.NONE=0,e.Query.wildcard.LEADING=1,e.Query.wildcard.TRAILING=2,e.Query.presence={OPTIONAL:1,REQUIRED:2,PROHIBITED:3},e.Query.prototype.clause=function(t){return"fields"in t||(t.fields=this.allFields),"boost"in t||(t.boost=1),"usePipeline"in t||(t.usePipeline=!0),"wildcard"in t||(t.wildcard=e.Query.wildcard.NONE),t.wildcard&e.Query.wildcard.LEADING&&t.term.charAt(0)!=e.Query.wildcard&&(t.term="*"+t.term),t.wildcard&e.Query.wildcard.TRAILING&&t.term.slice(-1)!=e.Query.wildcard&&(t.term=""+t.term+"*"),"presence"in t||(t.presence=e.Query.presence.OPTIONAL),this.clauses.push(t),this},e.Query.prototype.isNegated=function(){for(var t=0;t<this.clauses.length;t++)if(this.clauses[t].presence!=e.Query.presence.PROHIBITED)return!1;return!0},e.Query.prototype.term=function(t,r){if(Array.isArray(t))return t.forEach(function(t){this.term(t,e.utils.clone(r))},this),this;var i=r||{};return i.term=t.toString(),this.clause(i),this},e.QueryParseError=function(e,t,r){this.name="QueryParseError",this.message=e,this.start=t,this.end=r},e.QueryParseError.prototype=new Error,e.QueryLexer=function(e){this.lexemes=[],this.str=e,this.length=e.length,this.pos=0,this.start=0,this.escapeCharPositions=[]},e.QueryLexer.prototype.run=function(){for(var t=e.QueryLexer.lexText;t;)t=t(this)},e.QueryLexer.prototype.sliceString=function(){for(var e=[],t=this.start,r=this.pos,i=0;i<this.escapeCharPositions.length;i++)r=this.escapeCharPositions[i],e.push(this.str.slice(t,r)),t=r+1;return e.push(this.str.slice(t,this.pos)),this.escapeCharPositions.length=0,e.join("")},e.QueryLexer.prototype.emit=function(e){this.lexemes.push({type:e,str:this.sliceString(),start:this.start,end:this.pos}),this.start=this.pos},e.QueryLexer.prototype.escapeCharacter=function(){this.escapeCharPositions.push(this.pos-1),this.pos+=1},e.QueryLexer.prototype.next=function(){if(this.pos>=this.length)return e.QueryLexer.EOS;var t=this.str.charAt(this.pos);return this.pos+=1,t},e.QueryLexer.prototype.width=function(){return this.pos-this.start},e.QueryLexer.prototype.ignore=function(){this.start==this.pos&&(this.pos+=1),this.start=this.pos},e.QueryLexer.prototype.backup=function(){this.pos-=1},e.QueryLexer.prototype.acceptDigitRun=function(){var t,r;do t=this.next(),r=t.charCodeAt(0);while(r>47&&r<58);t!=e.QueryLexer.EOS&&this.backup()},e.QueryLexer.prototype.more=function(){return this.pos<this.length},e.QueryLexer.EOS="EOS",e.QueryLexer.FIELD="FIELD",e.QueryLexer.TERM="TERM",e.QueryLexer.EDIT_DISTANCE="EDIT_DISTANCE",e.QueryLexer.BOOST="BOOST",e.QueryLexer.PRESENCE="PRESENCE",e.QueryLexer.lexField=function(t){return t.backup(),t.emit(e.QueryLexer.FIELD),t.ignore(),e.QueryLexer.lexText},e.QueryLexer.lexTerm=function(t){if(t.width()>1&&(t.backup(),t.emit(e.QueryLexer.TERM)),t.ignore(),t.more())return e.QueryLexer.lexText},e.QueryLexer.lexEditDistance=function(t){return t.ignore(),t.acceptDigitRun(),t.emit(e.QueryLexer.EDIT_DISTANCE),e.QueryLexer.lexText},e.QueryLexer.lexBoost=function(t){return t.ignore(),t.acceptDigitRun(),t.emit(e.QueryLexer.BOOST),e.QueryLexer.lexText},e.QueryLexer.lexEOS=function(t){t.width()>0&&t.emit(e.QueryLexer.TERM)},e.QueryLexer.termSeparator=e.tokenizer.separator,e.QueryLexer.lexText=function(t){for(;;){var r=t.next();if(r==e.QueryLexer.EOS)return e.QueryLexer.lexEOS;if(92!=r.charCodeAt(0)){if(":"==r)return e.QueryLexer.lexField;if("~"==r)return t.backup(),t.width()>0&&t.emit(e.QueryLexer.TERM),e.QueryLexer.lexEditDistance;if("^"==r)return t.backup(),t.width()>0&&t.emit(e.QueryLexer.TERM),e.QueryLexer.lexBoost;if("+"==r&&1===t.width())return t.emit(e.QueryLexer.PRESENCE),e.QueryLexer.lexText;if("-"==r&&1===t.width())return t.emit(e.QueryLexer.PRESENCE),e.QueryLexer.lexText;if(r.match(e.QueryLexer.termSeparator))return e.QueryLexer.lexTerm}else t.escapeCharacter()}},e.QueryParser=function(t,r){this.lexer=new e.QueryLexer(t),this.query=r,this.currentClause={},this.lexemeIdx=0},e.QueryParser.prototype.parse=function(){this.lexer.run(),this.lexemes=this.lexer.lexemes;for(var t=e.QueryParser.parseClause;t;)t=t(this);return this.query},e.QueryParser.prototype.peekLexeme=function(){return this.lexemes[this.lexemeIdx]},e.QueryParser.prototype.consumeLexeme=function(){var e=this.peekLexeme();return this.lexemeIdx+=1,e},e.QueryParser.prototype.nextClause=function(){var e=this.currentClause;this.query.clause(e),this.currentClause={}},e.QueryParser.parseClause=function(t){var r=t.peekLexeme();if(void 0!=r)switch(r.type){case e.QueryLexer.PRESENCE:return e.QueryParser.parsePresence;case e.QueryLexer.FIELD:return e.QueryParser.parseField;case e.QueryLexer.TERM:return e.QueryParser.parseTerm;default:var i="expected either a field or a term, found "+r.type;throw r.str.length>=1&&(i+=" with value '"+r.str+"'"),new e.QueryParseError(i,r.start,r.end)}},e.QueryParser.parsePresence=function(t){var r=t.consumeLexeme();if(void 0!=r){switch(r.str){case"-":t.currentClause.presence=e.Query.presence.PROHIBITED;break;case"+":t.currentClause.presence=e.Query.presence.REQUIRED;break;default:var i="unrecognised presence operator'"+r.str+"'";throw new e.QueryParseError(i,r.start,r.end)}var n=t.peekLexeme();if(void 0==n){var i="expecting term or field, found nothing";throw new e.QueryParseError(i,r.start,r.end)}switch(n.type){case e.QueryLexer.FIELD:return e.QueryParser.parseField;case e.QueryLexer.TERM:return e.QueryParser.parseTerm;default:var i="expecting term or field, found '"+n.type+"'";throw new e.QueryParseError(i,n.start,n.end)}}},e.QueryParser.parseField=function(t){var r=t.consumeLexeme();if(void 0!=r){if(t.query.allFields.indexOf(r.str)==-1){var i=t.query.allFields.map(function(e){return"'"+e+"'"}).join(", "),n="unrecognised field '"+r.str+"', possible fields: "+i;throw new e.QueryParseError(n,r.start,r.end)}t.currentClause.fields=[r.str];var s=t.peekLexeme();if(void 0==s){var n="expecting term, found nothing";throw new e.QueryParseError(n,r.start,r.end)}switch(s.type){case e.QueryLexer.TERM:return e.QueryParser.parseTerm;default:var n="expecting term, found '"+s.type+"'";throw new e.QueryParseError(n,s.start,s.end)}}},e.QueryParser.parseTerm=function(t){var r=t.consumeLexeme();if(void 0!=r){t.currentClause.term=r.str.toLowerCase(),r.str.indexOf("*")!=-1&&(t.currentClause.usePipeline=!1);var i=t.peekLexeme();if(void 0==i)return void t.nextClause();switch(i.type){case e.QueryLexer.TERM:return t.nextClause(),e.QueryParser.parseTerm;case e.QueryLexer.FIELD:return t.nextClause(),e.QueryParser.parseField;case e.QueryLexer.EDIT_DISTANCE:return e.QueryParser.parseEditDistance;case e.QueryLexer.BOOST:return e.QueryParser.parseBoost;case e.QueryLexer.PRESENCE:return t.nextClause(),e.QueryParser.parsePresence;default:var n="Unexpected lexeme type '"+i.type+"'";throw new e.QueryParseError(n,i.start,i.end)}}},e.QueryParser.parseEditDistance=function(t){var r=t.consumeLexeme();if(void 0!=r){var i=parseInt(r.str,10);if(isNaN(i)){var n="edit distance must be numeric";throw new e.QueryParseError(n,r.start,r.end)}t.currentClause.editDistance=i;var s=t.peekLexeme();if(void 0==s)return void t.nextClause();switch(s.type){case e.QueryLexer.TERM:return t.nextClause(),e.QueryParser.parseTerm;case e.QueryLexer.FIELD:return t.nextClause(),e.QueryParser.parseField;case e.QueryLexer.EDIT_DISTANCE:return e.QueryParser.parseEditDistance;case e.QueryLexer.BOOST:return e.QueryParser.parseBoost;case e.QueryLexer.PRESENCE:return t.nextClause(),e.QueryParser.parsePresence;default:var n="Unexpected lexeme type '"+s.type+"'";throw new e.QueryParseError(n,s.start,s.end)}}},e.QueryParser.parseBoost=function(t){var r=t.consumeLexeme();if(void 0!=r){var i=parseInt(r.str,10);if(isNaN(i)){var n="boost must be numeric";throw new e.QueryParseError(n,r.start,r.end)}t.currentClause.boost=i;var s=t.peekLexeme();if(void 0==s)return void t.nextClause();switch(s.type){case e.QueryLexer.TERM:return t.nextClause(),e.QueryParser.parseTerm;case e.QueryLexer.FIELD:return t.nextClause(),e.QueryParser.parseField;case e.QueryLexer.EDIT_DISTANCE:return e.QueryParser.parseEditDistance;case e.QueryLexer.BOOST:return e.QueryParser.parseBoost;case e.QueryLexer.PRESENCE:return t.nextClause(),e.QueryParser.parsePresence;default:var n="Unexpected lexeme type '"+s.type+"'";throw new e.QueryParseError(n,s.start,s.end)}}},function(e,t){"function"==typeof define&&define.amd?define(t):"object"==typeof exports?module.exports=t():e.lunr=t()}(this,function(){return e})}();
diff --git a/assets/sass/_customize.scss b/assets/sass/_customize.scss
index 7b0c768..b0c174f 100644
--- a/assets/sass/_customize.scss
+++ b/assets/sass/_customize.scss
@@ -61,9 +61,9 @@
   }
 }
 
-#main article {
-  min-height: 100px;
-}
+// #main article {
+//   min-height: 100px;
+// }
 
 #TableOfContents ul ul,
 #TableOfContents ul ul ul,
diff --git a/assets/sass/_form-elements.scss b/assets/sass/_form-elements.scss
index 642f569..9135998 100644
--- a/assets/sass/_form-elements.scss
+++ b/assets/sass/_form-elements.scss
@@ -160,3 +160,37 @@ form input:-moz-ui-invalid {
     }
   }
 }
+
+.hide-element {
+  display: none;
+}
+
+.search-container {
+  width: 100%;
+  display: flex;
+  flex-flow: row nowrap;
+  align-items: center;
+  justify-content: space-evenly;
+  line-height: 1.3;
+}
+
+#site-search a {
+  color: hsl(0, 0%, 85%);
+  text-decoration: none;
+}
+
+#search-form .search-error.hide-element {
+  display: none;
+}
+
+.search-item {
+  font-weight: bold;
+}
+
+.search-error {
+  @include transition(all .5s ease-out);
+}
+
+.search-error-message {
+  @include transition(all .5s ease-out);
+}