vendor tsgo

tools/tsgo/internal/sourcemap/util.go

@@ -0,0 +1,29 @@
+package sourcemap
+
+import (
+	"strings"
+	"unicode"
+
+	"github.com/microsoft/typescript-go/internal/stringutil"
+)
+
+// Tries to find the sourceMappingURL comment at the end of a file.
+func TryGetSourceMappingURL(lineInfo *ECMALineInfo) string {
+	if lineInfo != nil {
+		for index := lineInfo.LineCount() - 1; index >= 0; index-- {
+			line := lineInfo.LineText(index)
+			line = strings.TrimLeftFunc(line, unicode.IsSpace)
+			line = strings.TrimRightFunc(line, stringutil.IsLineBreak)
+			if len(line) == 0 {
+				continue
+			}
+			if len(line) < 4 || !strings.HasPrefix(line, "//") || line[2] != '#' && line[2] != '@' || line[3] != ' ' {
+				break
+			}
+			if url, ok := strings.CutPrefix(line[4:], "sourceMappingURL="); ok {
+				return strings.TrimRightFunc(url, unicode.IsSpace)
+			}
+		}
+	}
+	return ""
+}