Implement documentation search (#8937)

* Implement documentation search

Signed-off-by: jolheiser <john.olheiser@gmail.com>
Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

docs/assets/js/search.js

@@ -0,0 +1,176 @@
+function ready(fn) {
+    if (document.readyState != 'loading') {
+        fn();
+    } else {
+        document.addEventListener('DOMContentLoaded', fn);
+    }
+}
+
+ready(doSearch);
+
+const summaryInclude = 60;
+const fuseOptions = {
+    shouldSort: true,
+    includeMatches: true,
+    matchAllTokens: true,
+    threshold: 0.0, // for parsing diacritics
+    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
+        }
+    ]
+};
+
+function param(name) {
+    return decodeURIComponent((location.search.split(name + '=')[1] || '').split('&')[0]).replace(/\+/g, ' ');
+}
+
+let searchQuery = param("s");
+
+function doSearch() {
+    if (searchQuery) {
+        document.getElementById("search-query").value = searchQuery;
+        executeSearch(searchQuery);
+    } else {
+        const para = document.createElement("P");
+        para.innerText = "Please enter a word or phrase above";
+        document.getElementById("search-results").appendChild(para);
+    }
+}
+
+function getJSON(url, fn) {
+    const request = new XMLHttpRequest();
+    request.open('GET', url, true);
+    request.onload = function () {
+        if (request.status >= 200 && request.status < 400) {
+            const data = JSON.parse(request.responseText);
+            fn(data);
+        } else {
+            console.log("Target reached on " + url + " with error " + request.status);
+        }
+    };
+    request.onerror = function () {
+        console.log("Connection error " + request.status);
+    };
+    request.send();
+}
+
+function executeSearch(searchQuery) {
+    getJSON("/" + document.LANG + "/index.json", function (data) {
+        const pages = data;
+        const fuse = new Fuse(pages, fuseOptions);
+        const result = fuse.search(searchQuery);
+        console.log({
+            "matches": result
+        });
+        document.getElementById("search-results").innerHTML = "";
+        if (result.length > 0) {
+            populateResults(result);
+        } else {
+            const para = document.createElement("P");
+            para.innerText = "No matches found";
+            document.getElementById("search-results").appendChild(para);
+        }
+    });
+}
+
+function populateResults(result) {
+    result.forEach(function (value, key) {
+        const content = value.item.contents;
+        let snippet = "";
+        const snippetHighlights = [];
+        if (fuseOptions.tokenize) {
+            snippetHighlights.push(searchQuery);
+            value.matches.forEach(function (mvalue) {
+                if (mvalue.key === "tags" || mvalue.key === "categories") {
+                    snippetHighlights.push(mvalue.value);
+                } else if (mvalue.key === "contents") {
+                    const ind = content.toLowerCase().indexOf(searchQuery.toLowerCase());
+                    const start = ind - summaryInclude > 0 ? ind - summaryInclude : 0;
+                    const end = ind + searchQuery.length + summaryInclude < content.length ? ind + searchQuery.length + summaryInclude : content.length;
+                    snippet += content.substring(start, end);
+                    if (ind > -1) {
+                        snippetHighlights.push(content.substring(ind, ind + searchQuery.length))
+                    } else {
+                        snippetHighlights.push(mvalue.value.substring(mvalue.indices[0][0], mvalue.indices[0][1] - mvalue.indices[0][0] + 1));
+                    }
+                }
+            });
+        }
+
+        if (snippet.length < 1) {
+            snippet += content.substring(0, summaryInclude * 2);
+        }
+        //pull template from hugo templarte definition
+        const templateDefinition = document.getElementById("search-result-template").innerHTML;
+        //replace values
+        const output = render(templateDefinition, {
+            key: key,
+            title: value.item.title,
+            link: value.item.permalink,
+            tags: value.item.tags,
+            categories: value.item.categories,
+            snippet: snippet
+        });
+        document.getElementById("search-results").appendChild(htmlToElement(output));
+
+        snippetHighlights.forEach(function (snipvalue) {
+            new Mark(document.getElementById("summary-" + key)).mark(snipvalue);
+        });
+
+    });
+}
+
+function render(templateString, data) {
+    let conditionalMatches, copy;
+    const 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 content.
+            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
+    let key, find, re;
+    for (key in data) {
+        find = '\\$\\{\\s*' + key + '\\s*\\}';
+        re = new RegExp(find, 'g');
+        templateString = templateString.replace(re, data[key]);
+    }
+    return templateString;
+}
+
+/**
+ * By Mark Amery: https://stackoverflow.com/a/35385518
+ * @param {String} HTML representing a single element
+ * @return {Element}
+ */
+function htmlToElement(html) {
+    const template = document.createElement('template');
+    html = html.trim(); // Never return a text node of whitespace as the result
+    template.innerHTML = html;
+    return template.content.firstChild;
+}