310 lines
9.9 KiB
JavaScript
310 lines
9.9 KiB
JavaScript
var suggestions = document.getElementById("suggestions");
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var userinput = document.getElementById("userinput");
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document.addEventListener("keydown", inputFocus);
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function inputFocus(e) {
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if (
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e.keyCode === 191 &&
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document.activeElement.tagName !== "INPUT" &&
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document.activeElement.tagName !== "TEXTAREA"
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) {
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e.preventDefault();
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userinput.focus();
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}
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if (e.keyCode === 27) {
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userinput.blur();
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suggestions.classList.add("d-none");
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}
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}
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document.addEventListener("click", function(event) {
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var isClickInsideElement = suggestions.contains(event.target);
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if (!isClickInsideElement) {
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suggestions.classList.add("d-none");
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}
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});
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/*
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Source:
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- https://dev.to/shubhamprakash/trap-focus-using-javascript-6a3
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*/
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document.addEventListener("keydown", suggestionFocus);
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function suggestionFocus(e) {
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const focusableSuggestions = suggestions.querySelectorAll("a");
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if (suggestions.classList.contains("d-none") || focusableSuggestions.length === 0) {
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return;
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}
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const focusable = [...focusableSuggestions];
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const index = focusable.indexOf(document.activeElement);
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let nextIndex = 0;
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if (e.keyCode === 38) {
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e.preventDefault();
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nextIndex = index > 0 ? index - 1 : 0;
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focusableSuggestions[nextIndex].focus();
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} else if (e.keyCode === 40) {
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e.preventDefault();
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nextIndex = index + 1 < focusable.length ? index + 1 : index;
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focusableSuggestions[nextIndex].focus();
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}
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}
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/*
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Source:
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- https://github.com/nextapps-de/flexsearch#index-documents-field-search
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- https://raw.githack.com/nextapps-de/flexsearch/master/demo/autocomplete.html
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- http://elasticlunr.com/
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- https://github.com/getzola/zola/blob/master/docs/static/search.js
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*/
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(function() {
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var index = elasticlunr.Index.load(window.searchIndex);
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userinput.addEventListener("input", show_results, true);
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suggestions.addEventListener("click", accept_suggestion, true);
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function show_results() {
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var value = this.value.trim();
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var options = {
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bool: "OR",
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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 results = index.search(value, options);
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var entry,
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childs = suggestions.childNodes;
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var i = 0,
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len = results.length;
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var items = value.split(/\s+/);
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suggestions.classList.remove("d-none");
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results.forEach(function(page) {
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if (page.doc.body !== "") {
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entry = document.createElement("div");
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entry.innerHTML = "<a href><span></span><span></span></a>";
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(a = entry.querySelector("a")),
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(t = entry.querySelector("span:first-child")),
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(d = entry.querySelector("span:nth-child(2)"));
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a.href = page.ref;
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t.textContent = page.doc.title;
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d.innerHTML = makeTeaser(page.doc.body, items);
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suggestions.appendChild(entry);
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}
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});
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while (childs.length > len) {
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suggestions.removeChild(childs[i]);
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}
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}
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function accept_suggestion() {
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while (suggestions.lastChild) {
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suggestions.removeChild(suggestions.lastChild);
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}
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return false;
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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(/[\s\n]/);
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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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if (body.length !== undefined && body.length > TEASER_MAX_WORDS * 10) {
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return body.substring(0, TEASER_MAX_WORDS * 10) + "...";
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} else {
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return body;
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}
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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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// Check the string is ascii characters or not
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var re = /^[\x00-\xff]+$/;
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if (word[1] !== TERM_WEIGHT && word[0].length >= 12 && !re.test(word[0])) {
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// If the string's length is too long, it maybe a Chinese/Japance/Korean article
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// if using substring method directly, it may occur error codes on emoji chars
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var strBefor = body.substring(word[2], startIndex);
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var strAfter = substringByByte(strBefor, 12);
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teaser.push(strAfter);
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} else {
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teaser.push(body.substring(word[2], startIndex));
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}
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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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})();
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// Get substring by bytes
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// If using JavaScript inline substring method, it will return error codes
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// Source: https://www.52pojie.cn/thread-1059814-1-1.html
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function substringByByte(str, maxLength) {
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var result = "";
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var flag = false;
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var len = 0;
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var length = 0;
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var length2 = 0;
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for (var i = 0; i < str.length; i++) {
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var code = str.codePointAt(i).toString(16);
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if (code.length > 4) {
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i++;
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if (i + 1 < str.length) {
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flag = str.codePointAt(i + 1).toString(16) == "200d";
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}
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}
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if (flag) {
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len += getByteByHex(code);
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if (i == str.length - 1) {
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length += len;
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if (length <= maxLength) {
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result += str.substr(length2, i - length2 + 1);
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} else {
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break;
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}
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}
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} else {
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if (len != 0) {
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length += len;
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length += getByteByHex(code);
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if (length <= maxLength) {
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result += str.substr(length2, i - length2 + 1);
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length2 = i + 1;
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} else {
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break;
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}
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len = 0;
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continue;
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}
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length += getByteByHex(code);
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if (length <= maxLength) {
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if (code.length <= 4) {
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result += str[i];
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} else {
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result += str[i - 1] + str[i];
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}
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length2 = i + 1;
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} else {
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break;
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}
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}
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}
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return result;
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}
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// Get the string bytes from binary
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function getByteByBinary(binaryCode) {
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// Binary system, starts with `0b` in ES6
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// Octal number system, starts with `0` in ES5 and starts with `0o` in ES6
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// Hexadecimal, starts with `0x` in both ES5 and ES6
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var byteLengthDatas = [0, 1, 2, 3, 4];
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var len = byteLengthDatas[Math.ceil(binaryCode.length / 8)];
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return len;
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}
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// Get the string bytes from hexadecimal
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function getByteByHex(hexCode) {
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return getByteByBinary(parseInt(hexCode, 16).toString(2));
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}
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