es6 可选链操作符

可选链操作符

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>es11-可选链操作符</title>

</head>
<body>


<script>

    function connect(config) {
        //const host = config && config.db && config.db.host;
        //?.可选链操作符
        const host = config?.db?.host;
        console.log(host);

    }

    connect({
        db:{
            host:'127.0.0.1'
        }
    })
</script>
</body>
</html>

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