可選鏈操作符
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>es11-可選鏈操作符</title> </head> <body> <script> function connect(config) { //const host = config && config.db && config.db.host; //?.可選鏈操作符 const host = config?.db?.host; console.log(host); } connect({ db:{ host:'127.0.0.1' } }) </script> </body> </html>