I know that the normal use case for this if statement is e.g.

var string = boolean ? "this" : "that";

I use jhint in my editor and when i try something like

boolean ? array.push("this") : array.slice("that",1);

jshint throws (W030) "Expected an assignment or function call and instead saw an expression"

So far the code always worked fine but maybe i was just lucky.

So my question is, why should i not use this pattern and what would be an alternative? Because writing

if(boolean){
    array.push("this");
} else {
    array.splice("that",1);
}

for such short instructions really give me the creeps.

thank you.

I know that the normal use case for this if statement is e.g.

var string = boolean ? "this" : "that";

I use jhint in my editor and when i try something like

boolean ? array.push("this") : array.slice("that",1);

jshint throws (W030) "Expected an assignment or function call and instead saw an expression"

So far the code always worked fine but maybe i was just lucky.

So my question is, why should i not use this pattern and what would be an alternative? Because writing

if(boolean){
    array.push("this");
} else {
    array.splice("that",1);
}

for such short instructions really give me the creeps.

thank you.

• javascript
• if-statement
• shorthand

Share Improve this question Follow asked Aug 23, 2014 at 8:58 user3144851user3144851 3922 bronze badges 3

• 8 JSLint plains about it for readability reasons. Which of the two you think is more readable? Code is read a lot more than it is written. It should not 'give you the creeps' to write one more line. – Benjamin Gruenbaum Commented Aug 23, 2014 at 8:59
• Add /*jshint -W030 */ to the top of the file to remove the warning, or updated your .jshint file. – Miguel Commented Aug 23, 2014 at 9:03
• 2 array.push modifies the array but array.slice does not. The portion after : has no effect, is there a raeson you used it? – Salman Arshad Commented Aug 23, 2014 at 9:17

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5 Answers 5

Sorted by: Reset to default 5

It is possible to wrap the ternary operator inside the void operator like this:

void(cond ? expr1 : expr2);

This achieves the desired result and passes JSHint. See JSFiddle and click JSHint button.

However, I remend the following syntax:

if (cond) {
    expr1;
} else {
    expr2;
}

Because it is more readable. Just because JavaScript lets you do strange things does not mean that you should.

What it plains about is you misappropriating the conditional operator. It is an operator not a control structure. So it lives in the category of such things things as +,-,*,/. That means you expect the first operand to be a boolean and the second and third to yield a return value.

The whole thing is meant to be short for

  if (boolean) {
   string ="this" ;
  } else {
   string ="that";
  }

It wants to return a value (which it can't in your case) and it expects you to use that value (which you don't). So the tenary if is not the thing to use for your case and as a result makes it far less readable.

You are using side effects in expressions to execute logic.

Indeed not very friendly code. It will work.

Just rewrite to distinct logic from expressions.

You can circumvent the jshint message using:

void(boolean ? array.push("this") : array.slice("that",1));

If you really want to use the ternary operater for this kind of operation in a clean way, then you can do it like this:

array[cond ? 'push' : 'slice'](cond ? "this" : "that", cond ? 1 : undefined);

or

array[cond ? 'push' : 'slice'].apply(null, cond ? ["this"] : ["that", 1]);

But anyway you may prefer a boring if statement.