website/themes/hugo-theme-wave/static/js/search.js

var lunrIndex,
    $results,
    pagesIndex;

// Initialize lunrjs using our generated index file
function initLunr() {
    // First retrieve the index file
    $.getJSON("/bower_components/lunr.js/PagesIndex.json")
        .done(function(index) {
            pagesIndex = index;

            // Set up lunrjs by declaring the fields we use
            // Also provide their boost level for the ranking
            lunrIndex = lunr(function() {
                this.field("title", {
                    boost: 10
                });
                this.field("tags", {
                    boost: 5
                });
                this.field("content");

                // ref is the result item identifier (I chose the page URL)
                this.ref("href");
            });

            // Feed lunr with each file and let lunr actually index them
            pagesIndex.forEach(function(page) {
                lunrIndex.add(page);
            });
        })
        .fail(function(jqxhr, textStatus, error) {
            var err = textStatus + ", " + error;
            console.error("Error getting Hugo index flie:", err);
        });
}

// Nothing crazy here, just hook up a listener on the input field
function initUI() {
    $results = $("#results");
    $("#search").keyup(function() {
        $results.empty();

        // Only trigger a search when 2 chars. at least have been provided
        var query = $(this).val();
        if (query.length < 2) {
            return;
        }

        var results = search(query);

        renderResults(results);
    });
}

/**
 * Trigger a search in lunr and transform the result
 *
 * @param  {String} query
 * @return {Array}  results
 */
function search(query) {
    // Find the item in our index corresponding to the lunr one to have more info
    // Lunr result: 
    //  {ref: "/section/page1", score: 0.2725657778206127}
    // Our result:
    //  {title:"Page1", href:"/section/page1", ...}
    return lunrIndex.search(query).map(function(result) {
            return pagesIndex.filter(function(page) {
                return page.href === result.ref;
            })[0];
        });
}

/**
 * Display the 10 first results
 *
 * @param  {Array} results to display
 */
function renderResults(results) {
    if (!results.length) {
        return;
    }

    // Only show the ten first results
    results.slice(0, 10).forEach(function(result) {
        var $result = $("<li>");
        $result.append($("<a>", {
            href: result.href,
            text: "» " + result.title
        }));
        $results.append($result);
    });
}

// Let's get started
initLunr();

$(document).ready(function() {
    initUI();
});