Improvements, add unfold.js

1 files changed, 86 insertions, 0 deletions

diff --git a/static/unfold.js b/static/unfold.js
new file mode 100644
index 0000000..e27dbb5
--- /dev/null
+++ b/static/unfold.js
@@ -0,0 +1,86 @@
+window.Unfold = {
+    activate: function (opts) {
+        const separator = opts.separator || "hr";
+        const content = opts.content || "main";
+        const theme = opts.theme || "moon";
+        const revealCdn = opts.revealCdn || "https://cdnjs.cloudflare.com/ajax/libs/reveal.js/3.6.0";
+
+        const contentElem = document.querySelector(content);
+        if (!contentElem) {
+            console.error(`Unfold: content element not found`);
+            return;
+        }
+
+        const nodes = [...contentElem.childNodes];
+
+        const newBody = document.createElement("body");
+        newBody.setAttribute("class", "reveal");
+        const slides = document.createElement("div");
+        slides.setAttribute("class", "slides");
+        newBody.appendChild(slides);
+
+        const newHead = document.createElement("head");
+
+        let currentSlide = document.createElement("section");
+        for (const node of nodes) {
+            if (node.hasAttribute && node.hasAttribute("data-unfold-hidden")) {
+                continue;
+            }
+
+            if (node.tagName?.toLowerCase() === separator.toLowerCase()) {
+                slides.appendChild(currentSlide);
+                currentSlide = document.createElement("section");
+            } else {
+                currentSlide.appendChild(node);
+            }
+        }
+        slides.appendChild(currentSlide);
+
+        const revealCssTag = document.createElement("link");
+        revealCssTag.rel = "stylesheet";
+        revealCssTag.href = `${revealCdn}/css/reveal.min.css`;
+        newHead.appendChild(revealCssTag);
+
+        const revealThemeCssTag = document.createElement("link");
+        revealThemeCssTag.rel = "stylesheet";
+        revealThemeCssTag.href = `${revealCdn}/css/theme/${theme}.css`;
+        newHead.appendChild(revealThemeCssTag);
+
+        const revealJsTag = document.createElement("script");
+        revealJsTag.src = `${revealCdn}/js/reveal.min.js`;
+        revealJsTag.onload = () => {
+	    // activate Reveal slideshow
+            Reveal.initialize();
+	    // fix vertical positioning issue that happens often
+	    setTimeout(() => Reveal.sync(), 100);
+        };
+        newHead.appendChild(revealJsTag);
+
+        document.head.replaceWith(newHead);
+        document.body.replaceWith(newBody);
+    },
+    bind: function (selector, opts = {}) {
+        const elem = document.querySelector(selector);
+        elem.addEventListener("click", () => {
+            Unfold.activate(opts)
+            // enable back button by hooking into History API
+            const qp = new URLSearchParams(location.search);
+            qp.set("unfold", "1");
+            history.pushState({}, "", `${location.protocol}//${location.host}${location.pathname}?${qp.toString()}`);
+        })
+
+        const qp = new URLSearchParams(location.search);
+        if (qp.get("unfold") === "1") {
+            Unfold.activate(opts)
+        }
+    }
+}
+
+const previousOnPopState = window.onpopstate;
+window.onpopstate = function() {
+    if (typeof previousOnPopState === "function") {
+	    previousOnPopState();
+    }
+    location.reload();
+};
+