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_javascript/modules/components/back-to-top.js

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+/**
+ * Reference: https://bootsnipp.com/snippets/featured/link-to-top-page
+ */
+
+export function back2top() {
+  const btn = document.getElementById('back-to-top');
+
+  window.addEventListener('scroll', () => {
+    if (window.scrollY > 50) {
+      btn.classList.add('show');
+    } else {
+      btn.classList.remove('show');
+    }
+  });
+
+  btn.addEventListener('click', () => {
+    window.scrollTo({ top: 0 });
+  });
+}