[Flight] Fix preload as attribute for stylesheets (facebook#34760)

unstubbable · web-flow · commit d44659744fd0 · 2025-10-10T21:40:56.000+02:00
Follow-up to facebook#34604. For a stylesheet, we need to render `<link rel="preload" as="style" ...>`, and not `<link rel="preload" as="stylesheet" ...>`. ([ref](https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/Attributes/rel/preload#what_types_of_content_can_be_preloaded)) fixes vercel/next.js#84569
diff --git a/packages/react-dom-bindings/src/server/ReactFlightServerConfigDOM.js b/packages/react-dom-bindings/src/server/ReactFlightServerConfigDOM.js
@@ -169,7 +169,7 @@ function processLink(props: Object, formatContext: FormatContext): void {
       return;
     }
     case 'stylesheet': {
-      preload(href, 'stylesheet', {
+      preload(href, 'style', {
         crossOrigin: props.crossOrigin,
         integrity: props.integrity,
         nonce: props.nonce,
diff --git a/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOM-test.js b/packages/react-server-dom-webpack/src/__tests__/ReactFlightDOM-test.js
@@ -2087,7 +2087,7 @@ describe('ReactFlightDOM', () => {
             media="(orientation: landscape)"
           />
           <link rel="modulepreload" href="module-resource" />
-          <link rel="preload" as="stylesheet" href="css-resource" />
+          <link rel="preload" as="style" href="css-resource" />
         </head>
         <body>
           <p>hello world</p>

Original file line number	Diff line number	Diff line change
`@@ -169,7 +169,7 @@ function processLink(props: Object, formatContext: FormatContext): void {`
`169`	`169`	`return;`
`170`	`170`	`}`
`171`	`171`	`case 'stylesheet': {`
`172`		`- preload(href, 'stylesheet', {`
	`172`	`+ preload(href, 'style', {`
`173`	`173`	`crossOrigin: props.crossOrigin,`
`174`	`174`	`integrity: props.integrity,`
`175`	`175`	`nonce: props.nonce,`