Fix sourcemap path problem (#450)

.editorconfig

@@ -1,3 +1,7 @@
 [*]
 indent_style = tab
 indent_size = 2
+
+[*.js]
+indent_style = space
+indent_size = 2

internal/bundler/linker.go

@@ -3436,7 +3436,7 @@ func (repr *chunkReprJS) generate(c *linkerContext, chunk *chunkInfo) func([]ast
 		}
 
 		if c.options.SourceMap != config.SourceMapNone {
-			sourceMap := c.generateSourceMapForChunk(compileResultsForSourceMap)
+			sourceMap := c.generateSourceMapForChunk(chunk.relDir, compileResultsForSourceMap)
 
 			// Store the generated source map
 			switch c.options.SourceMap {
@@ -3789,7 +3789,7 @@ func (c *linkerContext) preventExportsFromBeingRenamed(sourceIndex uint32) {
 	}
 }
 
-func (c *linkerContext) generateSourceMapForChunk(results []compileResultJS) []byte {
+func (c *linkerContext) generateSourceMapForChunk(relDir string, results []compileResultJS) []byte {
 	j := js_printer.Joiner{}
 	j.AddString("{\n  \"version\": 3")
 
@@ -3808,6 +3808,14 @@ func (c *linkerContext) generateSourceMapForChunk(results []compileResultJS) []b
 	}
 	j.AddString("]")
 
+	// Write the sourceRoot
+	j.AddString(",\n  \"sourceRoot\": \"")
+	if rel, ok := c.fs.Rel(c.fs.Join(c.options.AbsOutputDir, relDir), c.fs.Cwd()); ok {
+		// Replace Windows backward slashes with standard forward slashes.
+		j.AddString(strings.ReplaceAll(rel, "\\", "/"))
+	}
+	j.AddString("\"")
+
 	// Write the sourcesContent
 	j.AddString(",\n  \"sourcesContent\": [")
 	needComma = false

scripts/verify-source-map.js

@@ -314,7 +314,7 @@ async function check(kind, testCase, toSearch, { flags, entryPoints, crlf }) {
       const out2JsMap = await readFileAsync(path.join(tempDir, 'out2.js.map'), 'utf8')
 
       const out2Map = await new SourceMapConsumer(out2JsMap)
-      checkMap(out2Js, out2Map, path.relative(testDir, tempDir))
+      checkMap(out2Js, out2Map, path.join(path.relative(tempDir, testDir), path.basename(tempDir)))
     }
 
     if (!failed) rimraf.sync(tempDir, { disableGlob: true })