Javascript : Why typeof() is returing boolean value as a string?

Question

Maybe this question will look silly to you. But I have a quick one.

I'm learning JavaScript these days:

And trying to understand following code.

var name = true; 
console.log(typeof(name));

why the output is string ?

I'm expecting output will be boolean type. Why its returning as a string ?

because `window.name` - look it up - check using almost any other var name, like Name for example ... window.name is speshul — Jaromanda X, Dec 30 '16 at 06:44
rename the variable and check once. It's because of namespace — Mr.7, Dec 30 '16 at 06:45
try something non generic: `var a = true; console.log(typeof(a))` — Rajesh, Dec 30 '16 at 06:46
[`window.name`](https://developer.mozilla.org/en/docs/Web/API/Window/name).Why do starters start with obvious names? adding *"my"* to variable names fixes everything. — Adam Azad, Dec 30 '16 at 06:49
@Rajesh you got me... the output is ***boolean* this time... but it should behave in a same way with **name** variable right ? — Tushar Niras, Dec 30 '16 at 06:50
@AdamAzad so you mean to say...**name** is reserved work** or something ? — Tushar Niras, Dec 30 '16 at 06:52
@TusharNiras, it's a reserved variable, and protected from overwriting. :) — Adam Azad, Dec 30 '16 at 06:56
@TusharNiras just a pointer. Always wrap your code in a function. variables defined outside any function becomes a part of global scope — Rajesh, Dec 30 '16 at 06:58
Just to be clear: In browsers, `name` is a *predefined* global variable that converts any value that is assigned to it to a string. "Reserved (word)" as a very specific meaning when talking about programming languages, and `name` is not *reserved*. It doesn't have any meaning in JavaScript. — Felix Kling, Dec 30 '16 at 07:02

score 0 · Answer 1 · edited Dec 30 '16 at 06:55

0

typeof operator will give us the datatype of the variable in a string format. for example:

var a = false;
console.log(typeof a)
//Result: "boolean"

var b = {};
console.log(typeof b)
//Result: "object"


var name = true;
console.log(typeof name)
//Result: "string"

Every window having predefined variable called "name" and the datatype of this variable is "string". Open new window and in console just give name, it will give empty sting

edited Dec 30 '16 at 06:55

Rajesh

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answered Dec 30 '16 at 06:46

Aravinder

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This does not answer the question of why passing what looks like a Boolean outputs 'string' – Christopher Ronning Dec 30 '16 at 06:47
that's right I guess... as @JaromandaX said it's special variable may be ? and better not to use it.. :/ – Tushar Niras Dec 30 '16 at 06:57
@TusharNiras—not a special variable or reserved word, it's a special property of the [*window* object](https://developer.mozilla.org/en/docs/Web/API/Window), which is synonymous with the global object in browsers. Other types of host don't necessarily have such restrictions, it's not part of ECMAScript. – RobG Dec 30 '16 at 07:07

Javascript : Why typeof() is returing boolean value as a string?

1 Answers1