instance method String#blank
String#blank() → BooleanCheck if the string is "blank" — either empty (length of 0) or
containing only whitespace.
Example
''.blank();
//-> true
' '.blank();
//-> true
' a '.blank();
//-> falseString#blank() → BooleanCheck if the string is "blank" — either empty (length of 0) or
containing only whitespace.
''.blank();
//-> true
' '.blank();
//-> true
' a '.blank();
//-> false