feat: Allow dynamic options

artifacts/stats.json

@@ -0,0 +1,31 @@
+{
+  "index.js": {
+    "exports": [],
+    "facadeModuleId": "/Users/vio/work/relative-ci/rollup-plugin-stats/test/package/src/index.js",
+    "isDynamicEntry": false,
+    "isEntry": true,
+    "isImplicitEntry": false,
+    "moduleIds": [
+      "/Users/vio/work/relative-ci/rollup-plugin-stats/test/package/src/index.js"
+    ],
+    "name": "index",
+    "type": "chunk",
+    "dynamicImports": [],
+    "fileName": "index.js",
+    "implicitlyLoadedBefore": [],
+    "importedBindings": {},
+    "imports": [],
+    "modules": {
+      "/Users/vio/work/relative-ci/rollup-plugin-stats/test/package/src/index.js": {
+        "originalLength": 28,
+        "removedExports": [],
+        "renderedExports": [],
+        "renderedLength": 27
+      }
+    },
+    "referencedFiles": [],
+    "map": null,
+    "preliminaryFileName": "index.js",
+    "sourcemapFileName": null
+  }
+}

src/index.ts

@@ -1,6 +1,6 @@
 import path from 'node:path';
 import process from 'node:process';
-import type { Plugin } from 'rollup';
+import type { Plugin, OutputOptions } from 'rollup';
 
 import extractRollupStats, { type StatsOptions } from './extract';
 import { type RollupStatsWrite, rollupStatsWrite } from './write';
@@ -26,12 +26,18 @@ export type RollupStatsOptions = {
   write?: RollupStatsWrite;
 };
 
-function rollupStats(options: RollupStatsOptions = {}): Plugin {
-  const { fileName, stats: statsOptions, write = rollupStatsWrite } = options;
+type RollupStatsOptionsOrOutputOptions =
+  | RollupStatsOptions
+  | ((outputOptions: OutputOptions) => RollupStatsOptions);
 
+
+function rollupStats(options: RollupStatsOptionsOrOutputOptions): Plugin {
   return {
     name: PLUGIN_NAME,
     async generateBundle(context, bundle) {
+      const resolvedOptions = typeof options === 'function' ? options(context) : options;
+      const { fileName, stats: statsOptions, write = rollupStatsWrite } = resolvedOptions || {};
+
       const resolvedFileName = fileName || DEFAULT_FILE_NAME;
       const filepath = path.isAbsolute(resolvedFileName)
         ? resolvedFileName

test/package/package.test.js

@@ -4,7 +4,7 @@ import { describe, test, expect, beforeEach } from 'vitest';
 import { rollup } from 'rollup';
 import { vol } from 'memfs';
 
-import config, { relativeFileNameConfig, absoluteFileNameConfig } from './rollup.config';
+import config, { dynamicOptions, relativeFileNameConfig, absoluteFileNameConfig } from './rollup.config';
 
 describe('package test', () => {
   beforeEach(() => {
@@ -22,6 +22,17 @@ describe('package test', () => {
     });
   });
 
+  test('should output stats JSON file with explicit compilation file name', async () => {
+    const bundle = await rollup(dynamicOptions);
+    await bundle.generate(config.output);
+
+    const actual = await fs.readFile(path.join(config.output.dir, 'stats.es.json'), 'utf8');
+    const stats = JSON.parse(actual);
+    expect(stats['index.js']).toMatchObject({
+      fileName: 'index.js',
+    });
+  });
+
   test('should output stats JSON file with custom relative filename', async () => {
     const bundle = await rollup(relativeFileNameConfig);
     await bundle.generate(relativeFileNameConfig.output);

test/package/rollup.config.js

@@ -10,6 +10,17 @@ export default defineConfig({
   plugins: [stats()],
 });
 
+export const dynamicOptions = defineConfig({
+  input: path.join(__dirname, 'src/index.js'),
+  output: {
+    dir: 'dist',
+    format: 'commonjs',
+  },
+  plugins: [stats((options) => ({
+    fileName: `stats.${options.format}.json`,
+  }))],
+});
+
 export const relativeFileNameConfig = defineConfig({
   input: path.join(__dirname, 'src/index.js'),
   output: {