mirror of
https://github.com/getzola/zola
synced 2024-12-14 14:22:28 +00:00
180 lines
4.8 KiB
JavaScript
180 lines
4.8 KiB
JavaScript
function debounce(func, wait) {
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var timeout;
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return function () {
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var context = this;
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var args = arguments;
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clearTimeout(timeout);
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timeout = setTimeout(function () {
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timeout = null;
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func.apply(context, args);
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}, wait);
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};
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}
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// Taken from mdbook
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// The strategy is as follows:
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// First, assign a value to each word in the document:
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// Words that correspond to search terms (stemmer aware): 40
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// Normal words: 2
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// First word in a sentence: 8
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// Then use a sliding window with a constant number of words and count the
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// sum of the values of the words within the window. Then use the window that got the
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// maximum sum. If there are multiple maximas, then get the last one.
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// Enclose the terms in <b>.
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function makeTeaser(body, terms) {
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var TERM_WEIGHT = 40;
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var NORMAL_WORD_WEIGHT = 2;
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var FIRST_WORD_WEIGHT = 8;
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var TEASER_MAX_WORDS = 30;
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var stemmedTerms = terms.map(function (w) {
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return elasticlunr.stemmer(w.toLowerCase());
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});
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var termFound = false;
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var index = 0;
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var weighted = []; // contains elements of ["word", weight, index_in_document]
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// split in sentences, then words
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var sentences = body.toLowerCase().split(". ");
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for (var i in sentences) {
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var words = sentences[i].split(" ");
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var value = FIRST_WORD_WEIGHT;
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for (var j in words) {
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var word = words[j];
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if (word.length > 0) {
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for (var k in stemmedTerms) {
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if (elasticlunr.stemmer(word).startsWith(stemmedTerms[k])) {
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value = TERM_WEIGHT;
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termFound = true;
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}
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}
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weighted.push([word, value, index]);
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value = NORMAL_WORD_WEIGHT;
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}
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index += word.length;
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index += 1; // ' ' or '.' if last word in sentence
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}
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index += 1; // because we split at a two-char boundary '. '
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}
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if (weighted.length === 0) {
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return body;
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}
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var windowWeights = [];
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var windowSize = Math.min(weighted.length, TEASER_MAX_WORDS);
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// We add a window with all the weights first
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var curSum = 0;
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for (var i = 0; i < windowSize; i++) {
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curSum += weighted[i][1];
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}
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windowWeights.push(curSum);
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for (var i = 0; i < weighted.length - windowSize; i++) {
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curSum -= weighted[i][1];
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curSum += weighted[i + windowSize][1];
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windowWeights.push(curSum);
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}
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// If we didn't find the term, just pick the first window
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var maxSumIndex = 0;
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if (termFound) {
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var maxFound = 0;
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// backwards
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for (var i = windowWeights.length - 1; i >= 0; i--) {
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if (windowWeights[i] > maxFound) {
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maxFound = windowWeights[i];
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maxSumIndex = i;
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}
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}
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}
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var teaser = [];
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var startIndex = weighted[maxSumIndex][2];
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for (var i = maxSumIndex; i < maxSumIndex + windowSize; i++) {
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var word = weighted[i];
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if (startIndex < word[2]) {
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// missing text from index to start of `word`
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teaser.push(body.substring(startIndex, word[2]));
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startIndex = word[2];
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}
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// add <em/> around search terms
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if (word[1] === TERM_WEIGHT) {
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teaser.push("<b>");
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}
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startIndex = word[2] + word[0].length;
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teaser.push(body.substring(word[2], startIndex));
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if (word[1] === TERM_WEIGHT) {
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teaser.push("</b>");
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}
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}
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teaser.push("…");
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return teaser.join("");
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}
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function formatSearchResultItem(item, terms) {
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return '<div class="search-results__item">'
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+ `<a href="${item.ref}">${item.doc.title}</a>`
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+ `<div>${makeTeaser(item.doc.body, terms)}</div>`
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+ '</div>';
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}
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function initSearch() {
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var $searchInput = document.getElementById("search");
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var $searchResults = document.querySelector(".search-results");
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var $searchResultsItems = document.querySelector(".search-results__items");
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var MAX_ITEMS = 10;
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var options = {
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bool: "AND",
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fields: {
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title: {boost: 2},
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body: {boost: 1},
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}
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};
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var currentTerm = "";
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var index = elasticlunr.Index.load(window.searchIndex);
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$searchInput.addEventListener("keyup", debounce(function() {
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var term = $searchInput.value.trim();
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if (term === currentTerm || !index) {
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return;
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}
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$searchResults.style.display = term === "" ? "none" : "block";
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$searchResultsItems.innerHTML = "";
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if (term === "") {
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return;
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}
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var results = index.search(term, options);
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if (results.length === 0) {
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$searchResults.style.display = "none";
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return;
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}
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currentTerm = term;
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for (var i = 0; i < Math.min(results.length, MAX_ITEMS); i++) {
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var item = document.createElement("li");
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item.innerHTML = formatSearchResultItem(results[i], term.split(" "));
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$searchResultsItems.appendChild(item);
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}
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}, 150));
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}
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if (document.readyState === "complete" ||
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(document.readyState !== "loading" && !document.documentElement.doScroll)
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) {
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initSearch();
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} else {
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document.addEventListener("DOMContentLoaded", initSearch);
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}
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