From 6ca0cb0aee177a4c920f4e86d06544d0c51d9de3 Mon Sep 17 00:00:00 2001
From: xiaohj <51224469+xia0hj@users.noreply.github.com>
Date: Wed, 17 Jul 2024 23:16:14 +0800
Subject: [PATCH] fix: correct sourcemap with treeshake (#1069)

---
 src/plugin.ts               |  5 ++---
 src/plugins/tree-shaking.ts |  7 ++++---
 test/index.test.ts          | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/src/plugin.ts b/src/plugin.ts
index 25c9384c8..39cb46eb3 100644
--- a/src/plugin.ts
+++ b/src/plugin.ts
@@ -168,9 +168,8 @@ export class PluginContainer {
                 const newConsumer = await new SourceMapConsumer(
                   parseSourceMap(result.map),
                 )
-                const generator =
-                  SourceMapGenerator.fromSourceMap(originalConsumer)
-                generator.applySourceMap(newConsumer, info.path)
+                const generator = SourceMapGenerator.fromSourceMap(newConsumer)
+                generator.applySourceMap(originalConsumer, info.path)
                 info.map = generator.toJSON()
                 originalConsumer.destroy()
                 newConsumer.destroy()
diff --git a/src/plugins/tree-shaking.ts b/src/plugins/tree-shaking.ts
index 68368ab47..ad042e946 100644
--- a/src/plugins/tree-shaking.ts
+++ b/src/plugins/tree-shaking.ts
@@ -1,5 +1,6 @@
 import { rollup, type TreeshakingOptions, type TreeshakingPreset } from 'rollup'
 import type { Plugin } from '../plugin'
+import path from 'path'
 
 export type TreeshakingStrategy =
   | boolean
@@ -31,7 +32,7 @@ export const treeShakingPlugin = ({
               return false
             },
             load(id) {
-              if (id === info.path) return code
+              if (id === info.path) return { code, map: info.map }
             },
           },
         ],
@@ -44,14 +45,14 @@ export const treeShakingPlugin = ({
       const result = await bundle.generate({
         interop: 'auto',
         format: this.format,
-        file: 'out.js',
+        file: info.path,
         sourcemap: !!this.options.sourcemap,
         name,
       })
 
       for (const file of result.output) {
         if (file.type === 'chunk') {
-          if (file.fileName.endsWith('out.js')) {
+          if (file.fileName === path.basename(info.path)) {
             return {
               code: file.code,
               map: file.map,
diff --git a/test/index.test.ts b/test/index.test.ts
index 532b9296a..4cc39df51 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -856,3 +856,35 @@ test('should load postcss esm config', async () => {
   expect(outFiles).toEqual(['input.cjs', 'input.css'])
   expect(await getFileContent('dist/input.css')).toContain('color: blue;')
 })
+
+test('generate sourcemap with --treeshake', async () => {
+  const sourceCode = 'export function getValue(val: any){ return val; }'
+  const { outFiles, getFileContent } = await run(
+    getTestName(),
+    {
+      'src/input.ts': sourceCode,
+    },
+    {
+      entry: ['src/input.ts'],
+      flags: ['--treeshake', '--sourcemap', '--format=cjs,esm,iife'],
+    },
+  )
+
+  expect(outFiles.length).toBe(6)
+
+  await Promise.all(
+    outFiles
+      .filter((fileName) => fileName.endsWith('.map'))
+      .map(async (sourceMapFile) => {
+        const sourceMap = await getFileContent(`dist/${sourceMapFile}`).then(
+          (rawContent) => JSON.parse(rawContent),
+        )
+
+        expect(sourceMap.sources[0]).toBe('../src/input.ts')
+        expect(sourceMap.sourcesContent[0]).toBe(sourceCode)
+
+        const outputFileName = sourceMapFile.replace('.map', '')
+        expect(sourceMap.file).toBe(outputFileName)
+      }),
+  )
+})