[Fix] no-unknown-property: allow onLoad on source

See #3505 (comment)

Author: ljharb

CHANGELOG.md

@@ -11,6 +11,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 ### Fixed
 * [`no-array-index-key`]: consider flatMap ([#3530][] @k-yle)
 * [`jsx-curly-brace-presence`]: handle single and only expression template literals ([#3538][] @taozhou-glean)
+* [`no-unknown-property`]: allow `onLoad` on `source` (@ljharb)
 
 [#3538]: https://github.com/jsx-eslint/eslint-plugin-react/pull/3538
 [#3530]: https://github.com/jsx-eslint/eslint-plugin-react/pull/3530

lib/rules/no-unknown-property.js

@@ -81,7 +81,7 @@ const ATTRIBUTE_TAGS_MAP = {
   onEncrypted: ['audio', 'video'],
   onEnded: ['audio', 'video'],
   onError: ['audio', 'video', 'img', 'link', 'source', 'script', 'picture', 'iframe'],
-  onLoad: ['script', 'img', 'link', 'picture', 'iframe', 'object'],
+  onLoad: ['script', 'img', 'link', 'picture', 'iframe', 'object', 'source'],
   onLoadedData: ['audio', 'video'],
   onLoadedMetadata: ['audio', 'video'],
   onLoadStart: ['audio', 'video'],

tests/lib/rules/no-unknown-property.js

@@ -65,7 +65,7 @@ ruleTester.run('no-unknown-property', rule, {
     { code: '<picture inert={false} onError={foo} onLoad={bar} />' },
     { code: '<iframe onError={foo} onLoad={bar} />' },
     { code: '<script onLoad={bar} onError={foo} />' },
-    { code: '<source onError={foo} />' },
+    { code: '<source onLoad={bar} onError={foo} />' },
     { code: '<link onLoad={bar} onError={foo} />' },
     { code: '<link rel="preload" as="image" href="someHref" imageSrcSet="someImageSrcSet" imageSizes="someImageSizes" />' },
     { code: '<object onLoad={bar} />' },
@@ -459,7 +459,7 @@ ruleTester.run('no-unknown-property', rule, {
           data: {
             name: 'onLoad',
             tagName: 'div',
-            allowedTags: 'script, img, link, picture, iframe, object',
+            allowedTags: 'script, img, link, picture, iframe, object, source',
           },
         },
       ],