fix(react): ensure Accordion works when consumers have enabled tree-s…

…haking

We incorrectly caused `import "@u-elements/u-details"` to be tree-shaked
when `@digdir/designsystemet-react` was used in an application with tree-
shaking enabled.

This happened because we bundled several dependencies (including this one)
with our library, and our library has `"sideEffects": false`, implying that
any side-effect imports that happened within our library folder was safe to remove.

This was fixed by correctly marking all our dependencies as external, in
which case the application's build will correctly identify `"@u-elements/u-details"``
as having side-effects and thus not remove the import.

Closes #2477

.changeset/brave-months-shop.md

@@ -0,0 +1,5 @@
+---
+'@digdir/designsystemet-react': patch
+---
+
+Ensure Accordion works when consumers have enabled tree-shaking

packages/react/package.json

@@ -56,7 +56,6 @@
     "react-dom": "^18.3.1",
     "rimraf": "^6.0.1",
     "rollup": "^4.20.0",
-    "rollup-plugin-peer-deps-external": "^2.2.4",
     "typescript": "^5.5.4"
   }
 }

packages/react/rollup.config.js

@@ -1,6 +1,26 @@
 import commonjs from '@rollup/plugin-commonjs';
 import resolve from '@rollup/plugin-node-resolve';
-import peerDepsExternal from 'rollup-plugin-peer-deps-external';
+import pkg from './package.json';
+
+// These are dependencies, but are not in our package.json
+const implicitDependencies = [
+  '@digdir/designsystemet-theme',
+  '@digdir/designsystemet-css',
+  '@digdir/design-system-tokens',
+];
+
+const dependencies = Object.keys({
+  ...implicitDependencies,
+  ...pkg.dependencies,
+  ...pkg.peerDependencies,
+});
+
+/*
+Regexes to correctly mark submodules from dependencies as being external
+*/
+const dependenciesSubmodules = dependencies.map(
+  (dep) => new RegExp(`^${dep}/`),
+);
 
 export default [
   {
@@ -21,12 +41,7 @@ export default [
         preserveModulesRoot: 'tsc-build',
       },
     ],
-    external: [
-      /@digdir\/designsystemet-theme/,
-      /@digdir\/designsystemet-css/,
-      /@digdir\/design-system-tokens/,
-      /@navikt\/aksel-icons/,
-    ],
-    plugins: [peerDepsExternal(), resolve(), commonjs()],
+    external: [...dependencies, ...dependenciesSubmodules],
+    plugins: [resolve(), commonjs()],
   },
 ];

yarn.lock

@@ -2983,7 +2983,6 @@ __metadata:
     react-dom: "npm:^18.3.1"
     rimraf: "npm:^6.0.1"
     rollup: "npm:^4.20.0"
-    rollup-plugin-peer-deps-external: "npm:^2.2.4"
     typescript: "npm:^5.5.4"
   peerDependencies:
     react: ">=18.3.1"
@@ -14984,15 +14983,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"rollup-plugin-peer-deps-external@npm:^2.2.4":
-  version: 2.2.4
-  resolution: "rollup-plugin-peer-deps-external@npm:2.2.4"
-  peerDependencies:
-    rollup: "*"
-  checksum: 10/49b7b3f5ca14550146249b5fd86043bffb82a2c40750c80a1845c3b694fadde58435bae0c912ad8cb1c1ef6c1f8ad64914153793391cb13d52e2bc3aa2ac61e2
-  languageName: node
-  linkType: hard
-
 "rollup@npm:^4.13.0":
   version: 4.14.0
   resolution: "rollup@npm:4.14.0"