lots of cleanip

1 files changed, 50 insertions, 0 deletions

diff --git a/examples/demos/ScrollMenu.scala b/examples/demos/ScrollMenu.scala
new file mode 100644
index 0000000..ccab4e9
--- /dev/null
+++ b/examples/demos/ScrollMenu.scala
@@ -0,0 +1,50 @@
+import acyclic.file
+import org.scalajs.dom
+
+case class Tree[T](value: T, children: Vector[Tree[T]])
+
+case class MenuNode(frag: dom.HTMLElement, start: Int, end: Int)
+
+/**
+ * High performance scrollspy to
+ */
+class ScrollSpy(headers: Vector[Double], domTrees: Seq[Tree[MenuNode]]){
+  var scrolling = false
+  var lastSelected: dom.HTMLElement = null
+  def apply(threshold: Double) = if (!scrolling){
+    scrolling = true
+    dom.requestAnimationFrame((d: Double) => start(threshold))
+  }
+  def start(threshold: Double) = {
+    scrolling = false
+    def walkTree(tree: Tree[MenuNode]): Boolean = {
+      val Tree(MenuNode(menuItem, index, next), children) = tree
+      val before = headers(index) < threshold
+      val after = (next >= headers.length) || headers(next) > threshold
+      val win = before && after
+      if (win){
+        menuItem.classList.remove("hide")
+        var winFound = false
+
+        for(c <- tree.children){
+          val newWinFound = walkTree(c)
+          if (!winFound) c.value.frag.classList.add("selected")
+          else c.value.frag.classList.remove("selected")
+          winFound = winFound | newWinFound
+        }
+        if (!winFound) {
+          tree.children.foreach(_.value.frag.classList.remove("selected"))
+          if (lastSelected != null)
+            lastSelected.children(0).classList.remove("pure-menu-selected")
+          menuItem.children(0).classList.add("pure-menu-selected")
+          lastSelected = menuItem
+        }
+      }else{
+        menuItem.classList.add("hide")
+        menuItem.classList.remove("selected")
+      }
+      win
+    }
+    domTrees.map(walkTree)
+  }
+}
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