node.js console.log抛出了我未定义的内容

Question

 var sys = require("util");

When i try to run this code in the console, i get undefined as output. Even the below statement while executing throws me undefined.

 console.log("Hello World"); 

Output

 Hello World
 Undefined

Are we going to create our own server and write code with node.js?

Answer 1

The last undefined is result returned from console.log method:

node
> console.log('hey')
hey
undefined
> 

As you can see, first 'hey' printed by console.log, but console.log returns undefined as result of operation, and it printed to output.