Why does the console print undefined when I assign a variable?

Question

Hey pretty simple task I am trying to do.... I'm trying to take the text in my textbox and assign it to a var. When I run without the var I am getting text but if I assign it to a var I get undefined. Could someone explain this to me as it is very confusing to me?

That just returns undefined aswell... I was trying to use that originally — Seamy, Jan 30 '17 at 00:35
Maybe this answer can help you: http://stackoverflow.com/questions/22844840/why-does-javascript-variable-declaration-at-console-results-in-undefined-being — Elmer, Jan 30 '17 at 00:36
it's always better to add actual code to your question and not a screenshot of code. you can add your markup and js to a code snippet to illustrate the problem. — But those new buttons though.., Jan 30 '17 at 00:39
Per spec, `var` statements return _undefined_ http://es5.github.io/#x12.2 . The identifier `test` will still be initialised and set. Type `test;` and you will see its contents — Paul S., Jan 30 '17 at 00:42

Ulysse BN · Accepted Answer · 2017-01-30T00:42:29.977

5

TL;DR: It does not.

You can see content of your variable test, il will output the same thing as before. In fact it is the variable assignement that returns the undefined you see here.

For instance:

var test = 'Hello' // => undefined
test // => 'Hello'

Another case is printing your variable with console.log. If you do so, the return value will be undefined but the output will be your variable content (Hello here).

console.log(test) // return: undefined / print: Hello

edited Jan 30 '17 at 00:42

answered Jan 30 '17 at 00:36

Ulysse BN

10,116
7
54
82

i agree - doing variable assignments in the console usually spits out "undefined". try logging `test` after declaring it and see what you get – But those new buttons though.. Jan 30 '17 at 00:40
1

But if I try console.log(test) I still get undefined? – Seamy Jan 30 '17 at 00:42

Soviut · Answer 2 · 2017-01-30T00:38:40.957

0

What's returning undefined is the statement itself that you entered into the console, NOT the value of var text.

To see that console.log(text) or simply type text in the console.

edited Jan 30 '17 at 00:38

answered Jan 30 '17 at 00:35

Soviut

88,194
49
192
260

That is not related to the question OP asked – Ulysse BN Jan 30 '17 at 00:37
1

So now it’s a duplicate of mine – Ulysse BN Jan 30 '17 at 00:38
But if I try console.log(test) I still get undefined? – Seamy Jan 30 '17 at 00:43

Why does the console print undefined when I assign a variable?

2 Answers2