move some helpers to ts (#2399)

1 files changed, 106 insertions, 0 deletions

diff --git a/server/sonar-web/src/main/js/helpers/scrolling.ts b/server/sonar-web/src/main/js/helpers/scrolling.ts
new file mode 100644
index 00000000000..a36c6ef0789
--- /dev/null
+++ b/server/sonar-web/src/main/js/helpers/scrolling.ts
@@ -0,0 +1,106 @@
+/*
+ * SonarQube
+ * Copyright (C) 2009-2017 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+import { debounce } from 'lodash';
+
+const SCROLLING_DURATION = 100;
+const SCROLLING_INTERVAL = 10;
+const SCROLLING_STEPS = SCROLLING_DURATION / SCROLLING_INTERVAL;
+
+function isWindow(element: HTMLElement | Window): element is Window {
+  return element === window;
+}
+
+function getScrollPosition(element: HTMLElement | Window): number {
+  return isWindow(element) ? window.scrollY : element.scrollTop;
+}
+
+function scrollElement(element: HTMLElement | Window, position: number): void {
+  if (isWindow(element)) {
+    window.scrollTo(0, position);
+  } else {
+    element.scrollTop = position;
+  }
+}
+
+let smoothScrollTop = (y: number, parent: HTMLElement | Window) => {
+  let scrollTop = getScrollPosition(parent);
+  const scrollingDown = y > scrollTop;
+  const step = Math.ceil(Math.abs(y - scrollTop) / SCROLLING_STEPS);
+  let stepsDone = 0;
+
+  const interval = setInterval(() => {
+    if (scrollTop === y || SCROLLING_STEPS === stepsDone) {
+      clearInterval(interval);
+    } else {
+      let goal;
+      if (scrollingDown) {
+        goal = Math.min(y, scrollTop + step);
+      } else {
+        goal = Math.max(y, scrollTop - step);
+      }
+      stepsDone++;
+      scrollTop = goal;
+      scrollElement(parent, goal);
+    }
+  }, SCROLLING_INTERVAL);
+};
+
+smoothScrollTop = debounce(smoothScrollTop, SCROLLING_DURATION, { leading: true });
+
+export function scrollToElement(
+  element: HTMLElement,
+  options: {
+    topOffset?: number;
+    bottomOffset?: number;
+    parent?: HTMLElement;
+    smooth?: boolean;
+  }
+): void {
+  const opts = { topOffset: 0, bottomOffset: 0, parent: window, smooth: true, ...options };
+  const { parent } = opts;
+
+  const { top, bottom } = element.getBoundingClientRect();
+
+  const scrollTop = getScrollPosition(parent);
+
+  const height: number = isWindow(parent)
+    ? window.innerHeight
+    : parent.getBoundingClientRect().height;
+
+  const parentTop = isWindow(parent) ? 0 : parent.getBoundingClientRect().top;
+
+  if (top - parentTop < opts.topOffset) {
+    const goal = scrollTop - opts.topOffset + top - parentTop;
+    if (opts.smooth) {
+      smoothScrollTop(goal, parent);
+    } else {
+      scrollElement(parent, goal);
+    }
+  }
+
+  if (bottom - parentTop > height - opts.bottomOffset) {
+    const goal = scrollTop + bottom - parentTop - height + opts.bottomOffset;
+    if (opts.smooth) {
+      smoothScrollTop(goal, parent);
+    } else {
+      scrollElement(parent, goal);
+    }
+  }
+}