This closes #714 and closes #715, fix wrong worksheet index returned by NewSheet in some case, fix panic on formatted value with no built-in number format ID

1 files changed, 3 insertions, 0 deletions

diff --git a/cell.go b/cell.go
index 11c6836..bdda48c 100644
--- a/cell.go
+++ b/cell.go
@@ -770,6 +770,9 @@ func (f *File) formattedValue(s int, v string) string {
 	if ok != nil {
 		return ok(v, builtInNumFmt[numFmtId])
 	}
+	if styleSheet == nil || styleSheet.NumFmts == nil {
+		return v
+	}
 	for _, xlsxFmt := range styleSheet.NumFmts.NumFmt {
 		if xlsxFmt.NumFmtID == numFmtId {
 			format := strings.ToLower(xlsxFmt.FormatCode)