Add containerPosition prop for ToastContainer

src/ToastContainer.tsx

@@ -19,6 +19,7 @@ export interface ToastContainerProps
   extends BsPrefixProps,
     React.HTMLAttributes<HTMLElement> {
   position?: ToastPosition;
+  containerPosition?: string;
 }
 
 const propTypes = {
@@ -41,6 +42,13 @@ const propTypes = {
     'bottom-center',
     'bottom-end',
   ]),
+
+  /**
+   * By default the container is rendered with `position-absolute` utility class. Provide a string to use other `position-*` utility classes, or `false` to remove it.
+   *
+   * @default 'absolute'
+   */
+  containerPosition: PropTypes.string,
 };
 
 const positionClasses = {
@@ -63,6 +71,7 @@ const ToastContainer: BsPrefixRefForwardingComponent<
     {
       bsPrefix,
       position,
+      containerPosition = 'absolute',
       className,
       // Need to define the default "as" during prop destructuring to be compatible with styled-components github.com/react-bootstrap/react-bootstrap/issues/3595
       as: Component = 'div',
@@ -78,7 +87,8 @@ const ToastContainer: BsPrefixRefForwardingComponent<
         {...props}
         className={classNames(
           bsPrefix,
-          position && `position-absolute ${positionClasses[position]}`,
+          position &&
+            `position-${containerPosition} ${positionClasses[position]}`,
           className,
         )}
       />

test/ToastContainerSpec.tsx

@@ -1,53 +1,69 @@
 import { render } from '@testing-library/react';
 import ToastContainer, { ToastPosition } from '../src/ToastContainer';
 
-const expectedClasses: Record<ToastPosition, Array<string>> = {
-  'top-start': ['position-absolute', 'top-0', 'start-0'],
-  'top-center': [
-    'position-absolute',
-    'top-0',
-    'start-50',
-    'translate-middle-x',
-  ],
-  'top-end': ['position-absolute', 'top-0', 'end-0'],
-  'middle-start': [
-    'position-absolute',
-    'top-50',
-    'start-0',
-    'translate-middle-y',
-  ],
-  'middle-center': [
-    'position-absolute',
-    'top-50',
-    'start-50',
-    'translate-middle',
-  ],
-  'middle-end': ['position-absolute', 'top-50', 'end-0', 'translate-middle-y'],
-  'bottom-start': ['position-absolute', 'bottom-0', 'start-0'],
-  'bottom-center': [
-    'position-absolute',
-    'bottom-0',
-    'start-50',
-    'translate-middle-x',
-  ],
-  'bottom-end': ['position-absolute', 'bottom-0', 'end-0'],
+const expectedClassesWithoutPosition: Record<ToastPosition, Array<string>> = {
+  'top-start': ['top-0', 'start-0'],
+  'top-center': ['top-0', 'start-50', 'translate-middle-x'],
+  'top-end': ['top-0', 'end-0'],
+  'middle-start': ['top-50', 'start-0', 'translate-middle-y'],
+  'middle-center': ['top-50', 'start-50', 'translate-middle'],
+  'middle-end': ['top-50', 'end-0', 'translate-middle-y'],
+  'bottom-start': ['bottom-0', 'start-0'],
+  'bottom-center': ['bottom-0', 'start-50', 'translate-middle-x'],
+  'bottom-end': ['bottom-0', 'end-0'],
 };
 
+const createExpectedClasses = (containerPosition = 'absolute') =>
+  Object.fromEntries(
+    Object.entries(expectedClassesWithoutPosition).map(([key, value]) => [
+      key,
+      [`position-${containerPosition}`, ...value],
+    ]),
+  );
+
 describe('ToastContainer', () => {
   it('should render a basic toast container', () => {
     const { container } = render(<ToastContainer />);
     container.firstElementChild!.classList.contains('toast-container').should.be
       .true;
   });
 
-  Object.keys(expectedClasses).forEach((position: ToastPosition) => {
-    it(`should render position=${position}`, () => {
-      const { container } = render(<ToastContainer position={position} />);
-      expectedClasses[position].map(
-        (className) =>
-          container.firstElementChild!.classList.contains(className).should.be
-            .true,
-      );
+  describe('without containerPosition', () => {
+    const expectedClasses = createExpectedClasses();
+
+    Object.keys(expectedClasses).forEach((position: ToastPosition) => {
+      it(`should render classes for position=${position} with position-absolute`, () => {
+        const { container } = render(<ToastContainer position={position} />);
+        expectedClasses[position].map(
+          (className) =>
+            container.firstElementChild!.classList.contains(className).should.be
+              .true,
+        );
+      });
     });
   });
+
+  ['absolute', 'fixed', 'relative', 'sticky', 'custom'].forEach(
+    (containerPosition) => {
+      describe(`with containerPosition=${containerPosition}`, () => {
+        const expectedClasses = createExpectedClasses(containerPosition);
+
+        Object.keys(expectedClasses).forEach((position: ToastPosition) => {
+          it(`should render classes for position=${position} with position-${containerPosition}`, () => {
+            const { container } = render(
+              <ToastContainer
+                position={position}
+                containerPosition={containerPosition}
+              />,
+            );
+            expectedClasses[position].map(
+              (className) =>
+                container.firstElementChild!.classList.contains(className)
+                  .should.be.true,
+            );
+          });
+        });
+      });
+    },
+  );
 });