let vs var in the global scope

Question

Why this will print the names as expected:

var firstName = 'Charlie',
    lastName  = "Brown"

function showFullName() {
    console.log(this.firstName+' '+this.lastName);
}

window.showFullName();

but, if I replace 'var' for 'let', I will get 'undefined' for both firstName & lastName?

I also see that the variables declared using 'var' get attached to the window Object, but the ones declare using 'let'.

Appreciate the help.

score 3 · Accepted Answer · answered Mar 25 '17 at 21:07

3

Let allows to declare variables which are limited to a particular scope, can be block or expression. Where as var is used for global or local declaration. We can use var instead of let but the reverse fails.

answered Mar 25 '17 at 21:07

Sampath

599
5
12

let vs var in the global scope

1 Answers1