fix(rspeedy/react): should allow overriding SWC config

.changeset/young-parents-fry.md

@@ -0,0 +1,23 @@
+---
+"@lynx-js/react-rsbuild-plugin": patch
+---
+
+Support overriding SWC configuration.
+
+Now you can override configuration like `useDefineForClassFields` using `tools.swc`.
+
+```js
+import { defineConfig } from '@lynx-js/rspeedy';
+
+export default defineConfig({
+  tools: {
+    swc: {
+      jsc: {
+        transform: {
+          useDefineForClassFields: true,
+        },
+      },
+    },
+  },
+});
+```

packages/rspeedy/plugin-react/src/swc.ts

@@ -5,26 +5,25 @@ import type { RsbuildPluginAPI } from '@rsbuild/core'
 
 export function applySWC(api: RsbuildPluginAPI): void {
   api.modifyRsbuildConfig((config, { mergeRsbuildConfig }) => {
-    return mergeRsbuildConfig(config, {
+    return mergeRsbuildConfig({
       tools: {
-        swc(config) {
-          config.jsc ??= {}
-          config.jsc.transform ??= {}
-          config.jsc.transform.useDefineForClassFields = false
-          config.jsc.transform.optimizer ??= {}
-          config.jsc.transform.optimizer.simplify = true
-
-          config.jsc.parser ??= {
-            syntax: 'typescript',
-          }
-          if (config.jsc.parser.syntax === 'typescript') {
-            config.jsc.parser.tsx = false
-            config.jsc.parser.decorators = true
-          }
-
-          return config
+        swc: {
+          jsc: {
+            transform: {
+              // TODO: remove this in the next minor version
+              useDefineForClassFields: false,
+              optimizer: {
+                simplify: true,
+              },
+            },
+            parser: {
+              syntax: 'typescript',
+              tsx: false,
+              decorators: true,
+            },
+          },
         },
       },
-    })
+    }, config)
   })
 }

packages/rspeedy/plugin-react/test/swc-config.test.ts

@@ -3,7 +3,7 @@
 // LICENSE file in the root directory of this source tree.
 import { createRsbuild } from '@rsbuild/core'
 import type { RsbuildPluginAPI, Rspack } from '@rsbuild/core'
-import { describe, expect, test, vi } from 'vitest'
+import { assert, describe, expect, test, vi } from 'vitest'
 
 import { LAYERS, ReactWebpackPlugin } from '@lynx-js/react-webpack-plugin'
 
@@ -72,6 +72,41 @@ describe('SWC configuration', () => {
       `)
   })
 
+  test('with tools.swc', async () => {
+    vi.stubEnv('NODE_ENV', 'production')
+    const { pluginReactLynx } = await import('../src/pluginReactLynx.js')
+    const rsbuild = await createRsbuild({
+      rsbuildConfig: {
+        tools: {
+          swc: {
+            jsc: {
+              transform: {
+                useDefineForClassFields: true,
+                verbatimModuleSyntax: true,
+              },
+            },
+          },
+        },
+        plugins: [
+          pluginStubRspeedyAPI(),
+          pluginReactLynx(),
+        ],
+      },
+    })
+
+    const [config] = await rsbuild.initConfigs()
+
+    assert(config)
+
+    const swcOptions = getLoaderOptions<Rspack.SwcLoaderOptions>(
+      config,
+      'builtin:swc-loader',
+    )
+
+    expect(swcOptions?.jsc?.transform?.useDefineForClassFields).toBe(true)
+    expect(swcOptions?.jsc?.transform?.verbatimModuleSyntax).toBe(true)
+  })
+
   test('layers', async () => {
     vi.stubEnv('NODE_ENV', 'development')
     const { pluginReactLynx } = await import('../src/pluginReactLynx.js')