Javascript TRUE and "true" why someone uses string instead of boolean?

Question

I see in some javascript codes that people write something like this:

var myVar = "true";

//...

if(myVar == "true") {
     //...
}else{
     //...
}

Why people don't use TRUE or FALSE? As far as I know boolean type is obvious for browsers.

Or is just a poor code ... and try to never write in this way.

That's `true` and `false` actually (lower-case), but your analysis is right: better use actual booleans instead of strings. — Frédéric Hamidi, Jul 10 '12 at 12:14
And `var myVar = "false"; if (myVar) alert("O, hai!")` will show you alert as well. — Oleg V. Volkov, Jul 10 '12 at 14:09

Florian Margaine · Accepted Answer · 2012-07-10T14:01:12.307

7

It's just poor code. Try to never write in this way.

This kind of code is just horrible for maintainability. Both the == (instead of ===) and the true as string.

_{PS: besides, "true" == true // false. For the === argument, it's simply because true == 1 // true, and a lot of others look alike stuff like this.}

edited Jul 10 '12 at 14:01

answered Jul 10 '12 at 12:13

Florian Margaine

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score 4 · Answer 2 · edited May 23 '17 at 10:28

4

You should not do this, unless you really expect a string that contains true for some reason :). But even in that case, using strict equality (===) would be the right choice.

In the code example you are showing, this is simply a terrible way of writing code.

edited May 23 '17 at 10:28

Community

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answered Jul 10 '12 at 12:13

kapa

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In that case you should use strict equality to make it clear to anyone reading the code. – Matthew Jul 10 '12 at 12:14

score 1 · Answer 3 · answered Jul 10 '12 at 12:14

1

It's just poor code, as you say.

A "real" developer never writes if (condition == true), but only if (condition)

Could also be written if (true == condition). This is called Yoda style and is designed to prevent unwanted assignment of variables if you mistakenly write = instead of ==.

answered Jul 10 '12 at 12:14

Cyrille

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If you are talking about "real" developers, mentioning `===` would be worth it when testing for `true` :). – kapa Jul 10 '12 at 12:14
1

Agreed. I especially do this in PHP when testing for failures. – Cyrille Jul 10 '12 at 12:15

Javascript TRUE and "true" why someone uses string instead of boolean?

3 Answers3