From 9c0e44b67ec9eddf2d754fe2e2dcfcfb26ec7b3f Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Fri, 21 Jun 2024 14:37:14 -0400
Subject: [PATCH] Simplify props types

wip

wip
---
 .../src/components/transition/transition.tsx   |  6 ++----
 .../src/utils/render.test.tsx                  |  6 ++++--
 packages/@headlessui-react/src/utils/render.ts | 18 +++++++++++-------
 3 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/packages/@headlessui-react/src/components/transition/transition.tsx b/packages/@headlessui-react/src/components/transition/transition.tsx
index d2d4189ab4..a911b4919f 100644
--- a/packages/@headlessui-react/src/components/transition/transition.tsx
+++ b/packages/@headlessui-react/src/components/transition/transition.tsx
@@ -318,7 +318,6 @@ function TransitionChildFn<TTag extends ElementType = typeof DEFAULT_TRANSITION_
     leaveFrom,
     leaveTo,
 
-    // @ts-expect-error
     ...theirProps
   } = props as typeof props
   let container = useRef<HTMLElement | null>(null)
@@ -444,6 +443,8 @@ function TransitionChildFn<TTag extends ElementType = typeof DEFAULT_TRANSITION_
     className:
       classNames(
         // Incoming classes if any
+        // @ts-expect-error: className may not exist because not
+        // all components accept className (but all HTML elements do)
         theirProps.className,
 
         // Apply these classes immediately
@@ -498,7 +499,6 @@ function TransitionRootFn<TTag extends ElementType = typeof DEFAULT_TRANSITION_C
   props: TransitionRootProps<TTag>,
   ref: Ref<HTMLElement>
 ) {
-  // @ts-expect-error
   let { show, appear = false, unmount = true, ...theirProps } = props as typeof props
   let internalTransitionRef = useRef<HTMLElement | null>(null)
   let requiresRef = shouldForwardRef(props)
@@ -610,10 +610,8 @@ function ChildFn<TTag extends ElementType = typeof DEFAULT_TRANSITION_CHILD_TAG>
   return (
     <>
       {!hasTransitionContext && hasOpenClosedContext ? (
-        // @ts-expect-error This is an object
         <TransitionRoot ref={ref} {...props} />
       ) : (
-        // @ts-expect-error This is an object
         <InternalTransitionChild ref={ref} {...props} />
       )}
     </>
diff --git a/packages/@headlessui-react/src/utils/render.test.tsx b/packages/@headlessui-react/src/utils/render.test.tsx
index f6844c5751..ac28cad01e 100644
--- a/packages/@headlessui-react/src/utils/render.test.tsx
+++ b/packages/@headlessui-react/src/utils/render.test.tsx
@@ -424,9 +424,11 @@ describe('Features.Static | Features.RenderStrategy', () => {
   }
 
   // TODO: Can we "legit" test this? 🤔
-  it('should result in a typescript error', () => {
+  it.skip('should result in a typescript error', () => {
     testRender(
-      // @ts-expect-error static & unmount together are incompatible
+      // Properly setting up the types for this causes way more problems than it solves.
+      // Omit<…> has issues for instance when spreading the rest of the props on the component.
+      // @!ts-expect-error static & unmount together are incompatible
       <Dummy show={false} static unmount>
         Contents
       </Dummy>
diff --git a/packages/@headlessui-react/src/utils/render.ts b/packages/@headlessui-react/src/utils/render.ts
index f3eda31e10..4106c4b683 100644
--- a/packages/@headlessui-react/src/utils/render.ts
+++ b/packages/@headlessui-react/src/utils/render.ts
@@ -11,7 +11,7 @@ import {
   type ReactElement,
   type Ref,
 } from 'react'
-import type { Expand, Props, XOR, __ } from '../types'
+import type { Expand, Props } from '../types'
 import { classNames } from './class-names'
 import { match } from './match'
 
@@ -40,17 +40,21 @@ export enum RenderStrategy {
   Hidden,
 }
 
+type UnionToIntersection<T> = (T extends any ? (x: T) => any : never) extends (x: infer R) => any
+  ? R
+  : never
+
 type PropsForFeature<
   TPassedInFeatures extends RenderFeatures,
   TForFeature extends RenderFeatures,
   TProps,
-> = {
-  [P in TPassedInFeatures]: P extends TForFeature ? TProps : __
-}[TPassedInFeatures]
+> = TPassedInFeatures extends TForFeature ? TProps : {}
 
-export type PropsForFeatures<T extends RenderFeatures> = XOR<
-  PropsForFeature<T, RenderFeatures.Static, { static?: boolean }>,
-  PropsForFeature<T, RenderFeatures.RenderStrategy, { unmount?: boolean }>
+export type PropsForFeatures<T extends RenderFeatures> = Expand<
+  UnionToIntersection<
+    | PropsForFeature<T, RenderFeatures.Static, { static?: boolean }>
+    | PropsForFeature<T, RenderFeatures.RenderStrategy, { unmount?: boolean }>
+  >
 >
 
 export function render<TFeature extends RenderFeatures, TTag extends ElementType, TSlot>({