関連ワード:  typescript check if string is empty or undefined    typescript check if string is null or undefined    javascript check if string is empty or undefined    typescript check if string is null empty or undefined    typescript check if string is not empty or undefined    javascript check if string is null or undefined    javascript check if string is not empty or undefined    javascript check if string is null empty or undefined    typescript check if string is not null or undefined    javascript check if string is empty or whitespace or undefined  
結果 : typescript check if string is empty or undefined