Add support for passing props as HTML attributes

Previously, all properties were passed using React casing.
This does not work, particularly for complex cases such as SVG and XML,
in any other JSX runtime.
Instead, all other JSX runtimes converge on allowing HTML casing.

This adds an option for that.

Author: wooorm

index.js

@@ -1,5 +1,6 @@
 /**
  * @typedef {import('./lib/components.js').Components} Components
+ * @typedef {import('./lib/index.js').ElementAttributeNameCase} ElementAttributeNameCase
  * @typedef {import('./lib/index.js').Fragment} Fragment
  * @typedef {import('./lib/index.js').Jsx} Jsx
  * @typedef {import('./lib/index.js').JsxDev} JsxDev

lib/index.js

@@ -46,6 +46,12 @@
  * @typedef {'html' | 'svg'} Space
  *   Namespace.
  *
+ * @typedef {'react' | 'html'} ElementAttributeNameCase
+ *   Specify casing to use for attribute names.
+ *
+ *   React casing is for example `className`, `strokeLinecap`, `xmlLang`.
+ *   HTML casing is for example `class`, `stroke-linecap`, `xml:lang`.
+ *
  * @typedef Source
  *   Info about source.
  * @property {string | undefined} fileName
@@ -91,6 +97,8 @@
  *   Components to swap.
  * @property {boolean} passNode
  *   Pass `node` to components.
+ * @property {ElementAttributeNameCase} elementAttributeNameCase
+ *   Casing to use for attribute names.
  * @property {Schema} schema
  *   Current schema.
  * @property {unknown} Fragment
@@ -112,6 +120,8 @@
  *   `development: true`.
  * @property {boolean | null | undefined} [passNode=false]
  *   Pass the hast element node to components.
+ * @property {ElementAttributeNameCase | null | undefined} [elementAttributeNameCase='react']
+ *   Specify casing to use for attribute names.
  * @property {Space | null | undefined} [space='html']
  *   Whether `tree` is in the `'html'` or `'svg'` space.
  *
@@ -244,6 +254,7 @@ export function toJsxRuntime(tree, options) {
     Fragment: options.Fragment,
     schema: options.space === 'svg' ? svg : html,
     passNode: options.passNode || false,
+    elementAttributeNameCase: options.elementAttributeNameCase || 'react',
     components: options.components || {},
     filePath,
     create
@@ -479,7 +490,9 @@ function createProperty(state, node, prop, value) {
   }
 
   return [
-    info.space ? hastToReact[info.property] || info.property : info.attribute,
+    state.elementAttributeNameCase === 'react' && info.space
+      ? hastToReact[info.property] || info.property
+      : info.attribute,
     value
   ]
 }

readme.md

@@ -21,6 +21,7 @@ with an automatic JSX runtime.
     *   [`toJsxRuntime(tree, options)`](#tojsxruntimetree-options)
     *   [`Options`](#options)
     *   [`Components`](#components-1)
+    *   [`ElementAttributeNameCase`](#elementattributenamecase-1)
     *   [`Fragment`](#fragment-1)
     *   [`Jsx`](#jsx-1)
     *   [`JsxDev`](#jsxdev-1)
@@ -163,6 +164,11 @@ File path to the original source file (`string`, optional).
 Passed in source info to `jsxDEV` when using the automatic runtime with
 `development: true`.
 
+###### `elementAttributeNameCase`
+
+Specify casing to use for attribute names
+([`ElementAttributeNameCase`][elementattributenamecase], default: `'react'`).
+
 ###### `passNode`
 
 Pass the hast element node to components (`boolean`, default: `false`).
@@ -213,6 +219,19 @@ type Component<ComponentProps> =
   | (new (props: ComponentProps) => JSX.ElementClass)
 ```
 
+### `ElementAttributeNameCase`
+
+Specify casing to use for attribute names (TypeScript type).
+
+React casing is for example `className`, `strokeLinecap`, `xmlLang`.
+HTML casing is for example `class`, `stroke-linecap`, `xml:lang`.
+
+###### Type
+
+```ts
+type ElementAttributeNameCase = 'react' | 'html'
+```
+
 ### `Fragment`
 
 Represent the children, typically a symbol (TypeScript type).
@@ -281,7 +300,7 @@ type Props = {
     | number
     | boolean
     | undefined
-  children: Array<JSX.Element | string | null | undefined>
+  children: Array<JSX.Element | string | null | undefined> | undefined
   node?: Element | undefined
 }
 ```
@@ -397,6 +416,7 @@ followed by browsers such as Chrome, Firefox, and Safari.
 
 This package is fully typed with [TypeScript][].
 It exports the additional types [`Components`][components],
+[`ElementAttributeNameCase`][elementattributenamecase],
 [`Fragment`][fragment], [`Jsx`][jsx], [`JsxDev`][jsxdev], [`Options`][options],
 [`Props`][props], [`Source`][source], and [`Space`][Space].
 
@@ -513,3 +533,5 @@ abide by its terms.
 [space]: #space-1
 
 [components]: #components-1
+
+[elementattributenamecase]: #elementattributenamecase-1