1 files changed, 64 insertions, 0 deletions
diff --git a/popperjs/package/lib/dom-utils/getOffsetParent.js b/popperjs/package/lib/dom-utils/getOffsetParent.js
new file mode 100644
index 0000000..5300b0f
--- /dev/null
+++ b/popperjs/package/lib/dom-utils/getOffsetParent.js
@@ -0,0 +1,64 @@
+import getWindow from "./getWindow.js";
+import getNodeName from "./getNodeName.js";
+import getComputedStyle from "./getComputedStyle.js";
+import { isHTMLElement } from "./instanceOf.js";
+import isTableElement from "./isTableElement.js";
+import getParentNode from "./getParentNode.js";
+
+function getTrueOffsetParent(element) {
+  if (!isHTMLElement(element) || // https://github.com/popperjs/popper-core/issues/837
+  getComputedStyle(element).position === 'fixed') {
+    return null;
+  }
+
+  return element.offsetParent;
+} // `.offsetParent` reports `null` for fixed elements, while absolute elements
+// return the containing block
+
+
+function getContainingBlock(element) {
+  var isFirefox = navigator.userAgent.toLowerCase().indexOf('firefox') !== -1;
+  var isIE = navigator.userAgent.indexOf('Trident') !== -1;
+
+  if (isIE && isHTMLElement(element)) {
+    // In IE 9, 10 and 11 fixed elements containing block is always established by the viewport
+    var elementCss = getComputedStyle(element);
+
+    if (elementCss.position === 'fixed') {
+      return null;
+    }
+  }
+
+  var currentNode = getParentNode(element);
+
+  while (isHTMLElement(currentNode) && ['html', 'body'].indexOf(getNodeName(currentNode)) < 0) {
+    var css = getComputedStyle(currentNode); // This is non-exhaustive but covers the most common CSS properties that
+    // create a containing block.
+    // https://developer.mozilla.org/en-US/docs/Web/CSS/Containing_block#identifying_the_containing_block
+
+    if (css.transform !== 'none' || css.perspective !== 'none' || css.contain === 'paint' || ['transform', 'perspective'].indexOf(css.willChange) !== -1 || isFirefox && css.willChange === 'filter' || isFirefox && css.filter && css.filter !== 'none') {
+      return currentNode;
+    } else {
+      currentNode = currentNode.parentNode;
+    }
+  }
+
+  return null;
+} // Gets the closest ancestor positioned element. Handles some edge cases,
+// such as table ancestors and cross browser bugs.
+
+
+export default function getOffsetParent(element) {
+  var window = getWindow(element);
+  var offsetParent = getTrueOffsetParent(element);
+
+  while (offsetParent && isTableElement(offsetParent) && getComputedStyle(offsetParent).position === 'static') {
+    offsetParent = getTrueOffsetParent(offsetParent);
+  }
+
+  if (offsetParent && (getNodeName(offsetParent) === 'html' || getNodeName(offsetParent) === 'body' && getComputedStyle(offsetParent).position === 'static')) {
+    return window;
+  }
+
+  return offsetParent || getContainingBlock(element) || window;
+}
+\ No newline at end of file