How to write OR in Javascript?

Question

How do you write OR in Javascript?

Example :

if ( age **or** name == null ){
    do something
}

StackOverflow is not a good place to learn the very basic syntax of a language. Try a reference book or web site. — Paul Tomblin, Sep 04 '12 at 14:57
@drderp there are a few languages out there that allow or as a keyword. Fortran, for example. — Andreas Grapentin, Sep 04 '12 at 14:58
@drderp: Many languages allow you to write exactly that, making a "truthy/falsy" determination about the value of age. — Larry Lustig, Sep 04 '12 at 14:59
@DaveNewton: I agree, but the statement that no language will let you write that syntax is very, very misleading. — Larry Lustig, Sep 04 '12 at 15:33
@LarryLustig I was not trying to imply that no language would let you do that; you can do it, you just have to be sure of the results. — Jeremy Rodi, Sep 04 '12 at 16:54

score 16 · Accepted Answer · answered Sep 04 '12 at 14:56

Simply use:

if ( age == null || name == null ){    
    // do something    
}

Although, if you're simply testing to see if the variables have a value (and so are 'falsey' rather than equal to null) you could use instead:

if ( !age || !name ){    
    // do something    
}

References:

Logical operators in JavaScript.

score 10 · Answer 2 · edited May 23 '17 at 12:00

10

if (age == null || name == null) {

}

Note: You may want to see this thread, Why is null an object and what's the difference between null and undefined?, for information on null/undefined variables in JS.

edited May 23 '17 at 12:00

Community

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answered Sep 04 '12 at 14:55

user1103976

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`===` would be a smidge better – Matt Greer Sep 04 '12 at 14:56
Don´t just check for a null variable, it could be undefined also. See http://stackoverflow.com/questions/2559318/how-to-check-for-undefined-or-null-variable-in-javascript – pdjota Sep 04 '12 at 14:59
@pdjota `undefined == null` is true; you only need to differentiate if you're using `===` or specifically care about the difference. – Dave Newton Sep 04 '12 at 15:36

score 0 · Answer 3 · edited Oct 14 '12 at 10:54

0

The problem you are having is the way that or associates. (age or name == null) will actually be ((age or name) == null), which is not what you want to say. You want ((age == null) or (name == null)). When in doubt, insert parentheses. If you put in parentheses and evaluated, you would have seen that the situations became something like (true == null) and (false == null).

edited Oct 14 '12 at 10:54

Paul Fleming

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answered Sep 04 '12 at 15:02

Stephen Garle

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score 0 · Answer 4 · answered Jan 19 '19 at 13:17

0

We don't have OR operator in JavaScript, we use || instead, in your case do...:

if (age || name == null) {
  //do something
}

answered Jan 19 '19 at 13:17

Alireza

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How to write OR in Javascript?

4 Answers4

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