Detailed explanation of the difference between toString of and String of in js

We know that String () and. toString () are convertible to string types, but there is a difference between String () and. toString ()

1. toString () converts all data to strings, but excludes null and undefined

For example, converting false to string type

 var str = false.toString();
 console.log(str, typeof str);

The returned results are false, string

See if null and undefined can be converted to the string javascript

 var str = null.toString();
 console.log(str, typeof str);

Results the program reported an error

 var str = undefined.toString();
 console.log(str, typeof str);

The program also reports errors

. toString () in parentheses can write 1 number, representing the binary, corresponding to the binary string

Binary:. toString (2);

Octal:. toString (8);

Decimal:. toString (10);

106-ary:. toString (16);

2. The web page code String () can convert null and undefined into strings, but it cannot be converted into binary strings

For example, converting null to a string

 var str = String(null);
 console.log(str, typeof str);

The returned results are null, string

Convert undefined to String

 var str = String(undefined);
 console.log(str, typeof str);

The returned results are undefined, string