navigation functions

src/assets/js/navigation.js

+const path = require('path');
+const SHAPI = require( path.resolve(__dirname, './assets/js/api.js') );
+
+let api = new SHAPI();
+
+let DOMNavigationItems = document.querySelectorAll("aside .item");
+let DOMSections = document.querySelectorAll("section");
+
+let DOMSectionSongDetail = document.querySelector(".section-song-detail");
+
+let currentSection = 0;
+
+function NavigateToSection(sectionIndex) {
+    // Navigation
+    DOMNavigationItems.forEach(function(DOMNavigation) {
+        DOMNavigation.classList.remove("active");
+    });
+    DOMNavigationItems[sectionIndex].classList.add("active");
+
+    // Section
+    DOMSections.forEach(function(DOMSection) {
+        DOMSection.classList.remove("active");
+    });
+    DOMSections[sectionIndex].classList.add("active");
+    
+    currentSection = sectionIndex;
+}
+
+NavigateToSection(0);
+
+function NavigateToSongDetail(songId) {
+    // Navigation
+    DOMNavigationItems.forEach(function(DOMNavigation) {
+        DOMNavigation.classList.remove("active");
+    });
+
+    // Section
+    DOMSections.forEach(function(DOMSection) {
+        DOMSection.classList.remove("active");
+    });
+
+    // Load Detail
+    DOMSectionSongDetail.classList.add("active");
+}
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