JavaScript toString、String和stringify方法区别

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title>JavaScript toString与String方法区别</title>
    </head>
    <body>
        <script type="text/javascript">
            //一 toString限制
            // 报错Cannot read property 'toString' of undefined
            // console.log(undefined.toString())
            // 报错Cannot read property 'toString' of undefined
            //console.log(null.toString())

            //二 String无限制
            console.log(String(undefined))
            console.log(String(null))

            //三 toString可根据进制编码
            let num = 10;
            console.log(num.toString(2))
        </script>
    </body>
</html>

二、stringify也可以实现字符串化，并且健壮性也良好。

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title>JavaScript toString、String和stringify方法区别</title>
    </head>
    <body>
        <script type="text/javascript">
            let a = {
                age: undefined,
                name: null
            }
            //输出 {"name":null}
            console.log(JSON.stringify(a))
            let b;
            //输出 undefined
            console.log(JSON.stringify(b));
            let c = null;
            //输出 null
            console.log(JSON.stringify(c))
        </script>
    </body>
</html>