From 651bfc5cd284a259f429b50839c619dd1b94498a Mon Sep 17 00:00:00 2001
From: Jacky Zhao <j.zhao2k19@gmail.com>
Date: Mon, 07 Mar 2022 18:45:07 +0000
Subject: [PATCH] Merge pull request #62 from claudio4/hugo

---
 assets/js/search.js |  247 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 247 insertions(+), 0 deletions(-)

diff --git a/assets/js/search.js b/assets/js/search.js
new file mode 100644
index 0000000..34b7b62
--- /dev/null
+++ b/assets/js/search.js
@@ -0,0 +1,247 @@
+// code from https://github.com/danestves/markdown-to-text
+const removeMarkdown = (
+    markdown,
+    options = {
+        listUnicodeChar: false,
+        stripListLeaders: true,
+        gfm: true,
+        useImgAltText: false,
+        preserveLinks: false,
+    }
+) => {
+    let output = markdown || "";
+    output = output.replace(/^(-\s*?|\*\s*?|_\s*?){3,}\s*$/gm, "");
+
+    try {
+        if (options.stripListLeaders) {
+            if (options.listUnicodeChar)
+                output = output.replace(
+                    /^([\s\t]*)([\*\-\+]|\d+\.)\s+/gm,
+                    options.listUnicodeChar + " $1"
+                );
+            else output = output.replace(/^([\s\t]*)([\*\-\+]|\d+\.)\s+/gm, "$1");
+        }
+        if (options.gfm) {
+            output = output
+                .replace(/\n={2,}/g, "\n")
+                .replace(/~{3}.*\n/g, "")
+                .replace(/~~/g, "")
+                .replace(/`{3}.*\n/g, "");
+        }
+        if (options.preserveLinks) {
+            output = output.replace(/\[(.*?)\][\[\(](.*?)[\]\)]/g, "$1 ($2)")
+        }
+        output = output
+            .replace(/<[^>]*>/g, "")
+            .replace(/^[=\-]{2,}\s*$/g, "")
+            .replace(/\[\^.+?\](\: .*?$)?/g, "")
+            .replace(/\s{0,2}\[.*?\]: .*?$/g, "")
+            .replace(/\!\[(.*?)\][\[\(].*?[\]\)]/g, options.useImgAltText ? "$1" : "")
+            .replace(/\[(.*?)\][\[\(].*?[\]\)]/g, "$1")
+            .replace(/^\s{0,3}>\s?/g, "")
+            .replace(/(^|\n)\s{0,3}>\s?/g, "\n\n")
+            .replace(/^\s{1,2}\[(.*?)\]: (\S+)( ".*?")?\s*$/g, "")
+            .replace(
+                /^(\n)?\s{0,}#{1,6}\s+| {0,}(\n)?\s{0,}#{0,} {0,}(\n)?\s{0,}$/gm,
+                "$1$2$3"
+            )
+            .replace(/([\*_]{1,3})(\S.*?\S{0,1})\1/g, "$2")
+            .replace(/([\*_]{1,3})(\S.*?\S{0,1})\1/g, "$2")
+            .replace(/(`{3,})(.*?)\1/gm, "$2")
+            .replace(/`(.+?)`/g, "$1")
+            .replace(/\n{2,}/g, "\n\n");
+    } catch (e) {
+        console.error(e);
+        return markdown;
+    }
+    return output;
+};
+// -----
+
+(async function () {
+    const contentIndex = new FlexSearch.Document({
+        cache: true,
+        charset: "latin:extra",
+        optimize: true,
+        worker: true,
+        document: {
+            index: [{
+                field: "content",
+                tokenize: "strict",
+                context: {
+                    resolution: 5,
+                    depth: 3,
+                    bidirectional: true
+                },
+                suggest: true,
+            }, {
+                field: "title",
+                tokenize: "forward",
+            }]
+        }
+    })
+
+    const { content } = await fetchData
+    for (const [key, value] of Object.entries(content)) {
+        contentIndex.add({
+            id: key,
+            title: value.title,
+            content: removeMarkdown(value.content),
+        })
+    }
+
+    const highlight = (content, term) => {
+        const highlightWindow = 20
+        const tokenizedTerm = term.split(/\s+/).filter(t => t !== "")
+        const splitText = content.split(/\s+/).filter(t => t !== "")
+        const includesCheck = (token) => tokenizedTerm.some(term => token.toLowerCase().startsWith(term.toLowerCase()))
+
+        const occurrencesIndices = splitText
+            .map(includesCheck)
+
+        // calculate best index
+        let bestSum = 0
+        let bestIndex = 0
+        for (let i = 0; i < Math.max(occurrencesIndices.length - highlightWindow, 0); i++) {
+            const window = occurrencesIndices.slice(i, i + highlightWindow)
+            const windowSum = window.reduce((total, cur) => total + cur, 0)
+            if (windowSum >= bestSum) {
+                bestSum = windowSum
+                bestIndex = i
+            }
+        }
+
+        const startIndex = Math.max(bestIndex - highlightWindow, 0)
+        const endIndex = Math.min(startIndex + 2 * highlightWindow, splitText.length)
+        const mappedText = splitText
+            .slice(startIndex, endIndex)
+            .map(token => {
+                if (includesCheck(token)) {
+                    return `<span class="search-highlight">${token}</span>`
+                }
+                return token
+            })
+            .join(" ")
+            .replaceAll('</span> <span class="search-highlight">', " ")
+        return `${startIndex === 0 ? "" : "..."}${mappedText}${endIndex === splitText.length ? "" : "..."}`
+    }
+
+    const resultToHTML = ({ url, title, content, term }) => {
+        const text = removeMarkdown(content)
+        const resultTitle = highlight(title, term)
+        const resultText = highlight(text, term)
+        return `<button class="result-card" id="${url}">
+        <h3>${resultTitle}</h3>
+        <p>${resultText}</p>
+    </button>`
+    }
+
+    const redir = (id, term) => {
+        window.location.href = BASE_URL + `${id}#:~:text=${encodeURIComponent(term)}`
+    }
+
+    const formatForDisplay = id => ({
+        id,
+        url: id,
+        title: content[id].title,
+        content: content[id].content
+    })
+
+    const source = document.getElementById('search-bar')
+    const results = document.getElementById("results-container")
+    let term
+    source.addEventListener("keyup", (e) => {
+        if (e.key === "Enter") {
+            const anchor = document.getElementsByClassName("result-card")[0]
+            redir(anchor.id, term)
+        }
+    })
+    source.addEventListener('input', (e) => {
+        term = e.target.value
+        contentIndex.search(term, [
+            {
+                field: "content",
+                limit: 10,
+                suggest: true,
+            },
+            {
+                field: "title",
+                limit: 5,
+            }
+        ]).then(searchResults => {
+            const getByField = field => {
+                const results = searchResults.filter(x => x.field === field)
+                if (results.length === 0) {
+                    return []
+                } else {
+                    return [...results[0].result]
+                }
+            }
+            const allIds = new Set([...getByField('title'), ...getByField('content')])
+            const finalResults = [...allIds].map(formatForDisplay)
+
+            // display
+            if (finalResults.length === 0) {
+                results.innerHTML = `<button class="result-card">
+                    <h3>No results.</h3>
+                    <p>Try another search term?</p>
+                </button>`
+            } else {
+                results.innerHTML = finalResults
+                    .map(result => resultToHTML({
+                        ...result,
+                        term,
+                    }))
+                    .join("\n")
+                const anchors = document.getElementsByClassName("result-card");
+                [...anchors].forEach(anchor => {
+                    anchor.onclick = () => redir(anchor.id, term)
+                })
+            }
+        })
+    })
+
+
+    const searchContainer = document.getElementById("search-container")
+
+    function openSearch() {
+        if (searchContainer.style.display === "none" || searchContainer.style.display === "") {
+            source.value = ""
+            results.innerHTML = ""
+            searchContainer.style.display = "block"
+            source.focus()
+        } else {
+            searchContainer.style.display = "none"
+        }
+    }
+
+    function closeSearch() {
+        searchContainer.style.display = "none"
+    }
+
+    document.addEventListener('keydown', (event) => {
+        if (event.key === "/") {
+            event.preventDefault()
+            openSearch()
+        }
+        if (event.key === "Escape") {
+            event.preventDefault()
+            closeSearch()
+        }
+    })
+
+    const searchButton = document.getElementById("search-icon")
+    searchButton.addEventListener('click', (evt) => {
+        openSearch()
+    })
+    searchButton.addEventListener('keydown', (evt) => {
+        openSearch()
+    })
+    searchContainer.addEventListener('click', (evt) => {
+        closeSearch()
+    })
+    document.getElementById("search-space").addEventListener('click', (evt) => {
+        evt.stopPropagation()
+    })
+})()
+

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