# WhenStartsWith *Str
WhenStartsWith
invokes the given callback if the current string starts with the given value and returns a pointer to the current instance of Str.
# Signature
func (s *Str) WhenStartsWith(value string, callback func(s *Str) *Str) *Str
# Examples
str.New("go").
WhenStartsWith("go", func(s *str.Str) *str.Str {
return s.Append("lang")
}).
String()
// "golang"
str.New("go").
WhenStartsWith("gox", func(s *str.Str) *str.Str {
return s.Append("lang")
}).
String()
// "go"
str.New("").
WhenStartsWith("go", func(s *str.Str) *str.Str {
return s.Append("lang")
}).
String()
// ""