Fix Dialog cleanup when the Dialog becomes hidden (#2303)

* use the Dialog's parent as the root for the Intersection observer

We have some code that allows us to auto-close the dialog the moment it
gets hidden. This is useful if you use a dialog for a mobile menu and
you resizet he browser. If you wrap the dialog in a `md:hidden` then it
auto closes. If we don't do this, then the dialog is still locking the
scrolling, keeping the focus in the dialog, ... but it is not visible.

To solve this we use an `IntersectionObserver` to verify that the
`boundingClientRect` is "gone" (x = 0, y = 0, width = 0 and height = 0).

However, the intersection observer is not always triggered. This happens
if the main content is scrollable.

Setting the `root` of the `IntersectionObserver` to the parent of the
`Dialog` does seem to solve it.

Not 100% sure what causes this behaviour exactly.

* use a `ResizeObserver` instead of `IntersectionObserver`

* implement a `ResizeObserver` for the tests

* update changelog

Author: RobinMalfait

packages/@headlessui-react/CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Ensure the main tree and parent `Dialog` components are marked as `inert` ([#2290](https://github.com/tailwindlabs/headlessui/pull/2290))
 - Fix nested `Popover` components not opening ([#2293](https://github.com/tailwindlabs/headlessui/pull/2293))
 - Make React types more compatible with other libraries ([#2282](https://github.com/tailwindlabs/headlessui/pull/2282))
+- Fix `Dialog` cleanup when the `Dialog` becomes hidden ([#2303](https://github.com/tailwindlabs/headlessui/pull/2303))
 
 ## [1.7.11] - 2023-02-15
 

packages/@headlessui-react/src/components/dialog/dialog.test.tsx

@@ -30,7 +30,7 @@ import { OpenClosedProvider, State } from '../../internal/open-closed'
 jest.mock('../../hooks/use-id')
 
 // @ts-expect-error
-global.IntersectionObserver = class FakeIntersectionObserver {
+global.ResizeObserver = class FakeResizeObserver {
   observe() {}
   disconnect() {}
 }

packages/@headlessui-react/src/components/dialog/dialog.tsx

@@ -309,14 +309,10 @@ function DialogFn<TTag extends ElementType = typeof DEFAULT_DIALOG_TAG>(
     if (dialogState !== DialogStates.Open) return
     if (!internalDialogRef.current) return
 
-    let observer = new IntersectionObserver((entries) => {
+    let observer = new ResizeObserver((entries) => {
       for (let entry of entries) {
-        if (
-          entry.boundingClientRect.x === 0 &&
-          entry.boundingClientRect.y === 0 &&
-          entry.boundingClientRect.width === 0 &&
-          entry.boundingClientRect.height === 0
-        ) {
+        let rect = entry.target.getBoundingClientRect()
+        if (rect.x === 0 && rect.y === 0 && rect.width === 0 && rect.height === 0) {
           close()
         }
       }

packages/@headlessui-vue/CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Ensure the main tree and parent `Dialog` components are marked as `inert` ([#2290](https://github.com/tailwindlabs/headlessui/pull/2290))
 - Fix nested `Popover` components not opening ([#2293](https://github.com/tailwindlabs/headlessui/pull/2293))
 - Fix `change` event incorrectly getting called on `blur` ([#2296](https://github.com/tailwindlabs/headlessui/pull/2296))
+- Fix `Dialog` cleanup when the `Dialog` becomes hidden ([#2303](https://github.com/tailwindlabs/headlessui/pull/2303))
 
 ## [1.7.10] - 2023-02-15
 

packages/@headlessui-vue/src/components/dialog/dialog.test.ts

@@ -44,7 +44,7 @@ import { html } from '../../test-utils/html'
 import { useOpenClosedProvider, State } from '../../internal/open-closed'
 
 // @ts-expect-error
-global.IntersectionObserver = class FakeIntersectionObserver {
+global.ResizeObserver = class FakeResizeObserver {
   observe() {}
   disconnect() {}
 }

packages/@headlessui-vue/src/components/dialog/dialog.ts

@@ -280,14 +280,10 @@ export let Dialog = defineComponent({
       let container = dom(internalDialogRef)
       if (!container) return
 
-      let observer = new IntersectionObserver((entries) => {
+      let observer = new ResizeObserver((entries) => {
         for (let entry of entries) {
-          if (
-            entry.boundingClientRect.x === 0 &&
-            entry.boundingClientRect.y === 0 &&
-            entry.boundingClientRect.width === 0 &&
-            entry.boundingClientRect.height === 0
-          ) {
+          let rect = entry.target.getBoundingClientRect()
+          if (rect.x === 0 && rect.y === 0 && rect.width === 0 && rect.height === 0) {
             api.close()
           }
         }