Move more modules from flavours/glitch/utils to flavours/glitch

app/javascript/flavours/glitch/scroll.js

@@ -0,0 +1,32 @@
+const easingOutQuint = (x, t, b, c, d) => c * ((t = t / d - 1) * t * t * t * t + 1) + b;
+
+const scroll = (node, key, target) => {
+  const startTime = Date.now();
+  const offset    = node[key];
+  const gap       = target - offset;
+  const duration  = 1000;
+  let interrupt   = false;
+
+  const step = () => {
+    const elapsed    = Date.now() - startTime;
+    const percentage = elapsed / duration;
+
+    if (percentage > 1 || interrupt) {
+      return;
+    }
+
+    node[key] = easingOutQuint(0, elapsed, offset, gap, duration);
+    requestAnimationFrame(step);
+  };
+
+  step();
+
+  return () => {
+    interrupt = true;
+  };
+};
+
+const isScrollBehaviorSupported = 'scrollBehavior' in document.documentElement.style;
+
+export const scrollRight = (node, position) => isScrollBehaviorSupported ? node.scrollTo({ left: position, behavior: 'smooth' }) : scroll(node, 'scrollLeft', position);
+export const scrollTop = (node) => isScrollBehaviorSupported ? node.scrollTo({ top: 0, behavior: 'smooth' }) : scroll(node, 'scrollTop', 0);