这是console.log的简写吗？

Question

In advanced Javascript by Kyle Simpson he says that this:

var foo = "bar";

can be evaluated like this:

foo;

And that it's just a shortcut for console.log.

But when I try it nothing shows in the console.

Why is that?

Cheers

Answer 1

If you type that in the console and press Enter, the console will show you the result of the expression, which is the value of foo . The console shows you the resulting value of any expression you type into it. In the console itself, there's rarely any need to type console.log . (In fact, if you typed console.log(foo); into the console and pressed Enter, you'd see the value of foo followed by undefined , because console.log returns undefined , so the console shows you that value.)

In code not typed into the console itself, no, foo; is not shorthand for console.log(foo); . It's just an ExpressionStatement sitting on its own that basically does nothing.

Answer 2

foo; is not a shorthand for console.log(foo) .

Suppose in code, you have defined a variable var name="mrid" you'll have to write console.log(name) to print it in console. But you can directly type name in console and it will print it's value.