1 files changed, 70 insertions, 0 deletions
diff --git a/js/src/util/scrollbar.js b/js/src/util/scrollbar.js
new file mode 100644
index 000000000..d2f3919e6
--- /dev/null
+++ b/js/src/util/scrollbar.js
@@ -0,0 +1,70 @@
+/**
+ * --------------------------------------------------------------------------
+ * Bootstrap (v5.0.0-beta2): util/scrollBar.js
+ * Licensed under MIT (https://github.com/twbs/bootstrap/blob/main/LICENSE)
+ * --------------------------------------------------------------------------
+ */
+
+import SelectorEngine from '../dom/selector-engine'
+import Manipulator from '../dom/manipulator'
+
+const SELECTOR_FIXED_CONTENT = '.fixed-top, .fixed-bottom, .is-fixed'
+const SELECTOR_STICKY_CONTENT = '.sticky-top'
+
+const getWidth = () => {
+  // https://developer.mozilla.org/en-US/docs/Web/API/Window/innerWidth#usage_notes
+  const documentWidth = document.documentElement.clientWidth
+  return Math.abs(window.innerWidth - documentWidth)
+}
+
+const hide = (width = getWidth()) => {
+  document.body.style.overflow = 'hidden'
+  _setElementAttributes(SELECTOR_FIXED_CONTENT, 'paddingRight', calculatedValue => calculatedValue + width)
+  _setElementAttributes(SELECTOR_STICKY_CONTENT, 'marginRight', calculatedValue => calculatedValue - width)
+  _setElementAttributes('body', 'paddingRight', calculatedValue => calculatedValue + width)
+}
+
+const _setElementAttributes = (selector, styleProp, callback) => {
+  const scrollbarWidth = getWidth()
+  SelectorEngine.find(selector)
+    .forEach(element => {
+      if (element !== document.body && window.innerWidth > element.clientWidth + scrollbarWidth) {
+        return
+      }
+
+      const actualValue = element.style[styleProp]
+      const calculatedValue = window.getComputedStyle(element)[styleProp]
+      Manipulator.setDataAttribute(element, styleProp, actualValue)
+      element.style[styleProp] = callback(Number.parseFloat(calculatedValue)) + 'px'
+    })
+}
+
+const reset = () => {
+  document.body.style.overflow = 'auto'
+  _resetElementAttributes(SELECTOR_FIXED_CONTENT, 'paddingRight')
+  _resetElementAttributes(SELECTOR_STICKY_CONTENT, 'marginRight')
+  _resetElementAttributes('body', 'paddingRight')
+}
+
+const _resetElementAttributes = (selector, styleProp) => {
+  SelectorEngine.find(selector).forEach(element => {
+    const value = Manipulator.getDataAttribute(element, styleProp)
+    if (typeof value === 'undefined' && element === document.body) {
+      element.style.removeProperty(styleProp)
+    } else {
+      Manipulator.removeDataAttribute(element, styleProp)
+      element.style[styleProp] = value
+    }
+  })
+}
+
+const isBodyOverflowing = () => {
+  return getWidth() > 0
+}
+
+export {
+  getWidth,
+  hide,
+  isBodyOverflowing,
+  reset
+}