From 01466aed2f827586a3c612b46e94d139075647e4 Mon Sep 17 00:00:00 2001
From: Curtis Cummings <curtis@aquil.io>
Date: Tue, 9 Jul 2019 15:08:30 -0400
Subject: [PATCH] fix(DropdownMenu): Allow positionFixed prop to be passed
 through (#1538)

Allow the positionFixed prop to be passed through to the Popper component

Fixes #1473
---
 docs/lib/Components/DropdownsPage.js |  4 +++-
 src/DropdownMenu.js                  |  5 ++++-
 src/__tests__/DropdownMenu.spec.js   | 11 +++++++++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/docs/lib/Components/DropdownsPage.js b/docs/lib/Components/DropdownsPage.js
index cdc86b236..302cb63e0 100644
--- a/docs/lib/Components/DropdownsPage.js
+++ b/docs/lib/Components/DropdownsPage.js
@@ -94,7 +94,9 @@ DropdownMenu.propTypes = {
   cssModule: PropTypes.object,
   // Custom modifiers that are passed to DropdownMenu.js, see https://popper.js.org/popper-documentation.html#modifiers
   modifiers: PropTypes.object,
-  persist: PropTypes.bool // presist the popper, even when closed. See #779 for reasoning
+  persist: PropTypes.bool, // presist the popper, even when closed. See #779 for reasoning
+  // passed to popper, see https://popper.js.org/popper-documentation.html#Popper.Defaults.positionFixed
+  positionFixed: PropTypes.bool
 };
 
 DropdownItem.propTypes = {
diff --git a/src/DropdownMenu.js b/src/DropdownMenu.js
index 7e23327c4..119d8615e 100644
--- a/src/DropdownMenu.js
+++ b/src/DropdownMenu.js
@@ -14,6 +14,7 @@ const propTypes = {
   className: PropTypes.string,
   cssModule: PropTypes.object,
   persist: PropTypes.bool,
+  positionFixed: PropTypes.bool,
 };
 
 const defaultProps = {
@@ -33,7 +34,7 @@ const directionPositionMap = {
 class DropdownMenu extends React.Component { 
 
   render() {
-    const { className, cssModule, right, tag, flip, modifiers, persist, ...attrs } = this.props;
+    const { className, cssModule, right, tag, flip, modifiers, persist, positionFixed, ...attrs } = this.props;
     const classes = mapToCssModules(classNames(
       className,
       'dropdown-menu',
@@ -54,11 +55,13 @@ class DropdownMenu extends React.Component {
         ...modifiers,
         ...noFlipModifier,
       } : modifiers;
+      const popperPositionFixed = !!positionFixed;
 
       return (
         <Popper
           placement={poperPlacement}
           modifiers={poperModifiers}
+          positionFixed={popperPositionFixed}
         >
           {({ ref, style, placement }) => (
             <Tag
diff --git a/src/__tests__/DropdownMenu.spec.js b/src/__tests__/DropdownMenu.spec.js
index e447b67f6..84999792f 100644
--- a/src/__tests__/DropdownMenu.spec.js
+++ b/src/__tests__/DropdownMenu.spec.js
@@ -160,6 +160,17 @@ describe('DropdownMenu', () => {
     expect(wrapper.find(Popper).prop('modifiers')).toEqual({ flip: { enabled: false } });
   });
 
+  it('should position using fixed mode when positionFixed is true', () => {
+    isOpen = true;
+    const wrapper = mount(
+      <DropdownContext.Provider value={{ isOpen, direction, inNavbar }}>
+        <DropdownMenu positionFixed>Ello world</DropdownMenu>
+      </DropdownContext.Provider>
+    );
+
+    expect(wrapper.find(Popper).prop('positionFixed')).toBe(true);
+  });
+
   it('should not render multiple children when isOpen is false', () => {
     const wrapper = mount(
       <DropdownContext.Provider value={{ isOpen, direction, inNavbar }}>