Added configuration code that scours the current file path and workin…

…g directory tree for an `.swcrc` config file.

If it finds one then it loads that file from disk and takes precidence over the code config

src/preset.ts

@@ -1,3 +1,5 @@
+import Path from "path";
+import Fs from "fs";
 import { getProjectRoot } from "@storybook/core-common";
 import type { Options } from "@storybook/types";
 import type { Options as SwcOptions } from "@swc/core";
@@ -8,6 +10,24 @@ const virtualModuleFiles = [
   /storybook-stories\.js$/,
 ];
 
+function findSWCConfigFile() {
+  const basePaths = [process.cwd(), Path.resolve(__dirname)];
+  for (const basePath of basePaths) {
+    const pathParts = basePath.split(/[\\\/]/);
+    while (pathParts.length) {
+      const dir = Path.join(...pathParts);
+      const file = Path.join(dir, ".swcrc");
+      if (Fs.existsSync(file)) {
+        return file;
+      }
+
+      pathParts.pop();
+    }
+  }
+
+  return null;
+}
+
 export const webpackFinal = async (config: Configuration, options: Options) => {
   const swcOptions = await options.presets.apply("swc", {}, options);
   const typescriptOptions = await options.presets.apply(
@@ -16,24 +36,29 @@ export const webpackFinal = async (config: Configuration, options: Options) => {
     options,
   );
 
-  const swcFinalOptions: SwcOptions = {
-    ...swcOptions,
-    env: {
-      ...(swcOptions?.env ?? {}),
-      // Transpiles the broken syntax to the closest non-broken modern syntax.
-      // E.g. it won't transpile parameter destructuring in Safari
-      // which would break how we detect if the mount context property is used in the play function.
-      bugfixes: swcOptions?.env?.bugfixes ?? true,
-    },
-    jsc: {
-      ...(swcOptions.jsc ?? {}),
-      parser: swcOptions.jsc?.parser ?? {
-        syntax: "typescript",
-        tsx: true,
-        dynamicImport: true,
-      },
-    },
-  };
+  const swcConfigFile: string | null = findSWCConfigFile();
+
+  const swcFinalOptions: SwcOptions =
+    !!swcConfigFile && Fs.existsSync(swcConfigFile)
+      ? JSON.parse(Fs.readFileSync(swcConfigFile, "utf-8"))
+      : {
+          ...swcOptions,
+          env: {
+            ...(swcOptions?.env ?? {}),
+            // Transpiles the broken syntax to the closest non-broken modern syntax.
+            // E.g. it won't transpile parameter destructuring in Safari
+            // which would break how we detect if the mount context property is used in the play function.
+            bugfixes: swcOptions?.env?.bugfixes ?? true,
+          },
+          jsc: {
+            ...(swcOptions.jsc ?? {}),
+            parser: swcOptions.jsc?.parser ?? {
+              syntax: "typescript",
+              tsx: true,
+              dynamicImport: true,
+            },
+          },
+        };
 
   config.module = {
     ...(config.module || {}),