Why is this ternary operator invalid in JS

Question

var truth = true;
(truth) ? console.log('It is true') : throw new Error('It is not true');

Do ternary operators only accept specific types of objects?

You could make a function: function _throw(msg) { throw new Error(msg); } then use it in the conditional operator: truth ? console.log("true") : _throw("It is not true"); — I Hate Lazy
– I Hate Lazy, Commented Nov 21, 2012 at 22:33

antlersoft · Accepted Answer · 2012-11-21 22:29:26Z

18

javascript distinguishes between statements and expressions. The ternary operator only handles expressions; throw is a statement.

answered Nov 21, 2012 at 22:29

antlersoft

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Comments

LWChris · Accepted Answer · 2012-11-21 22:43:20Z

4

It does work, but the problem is the throw statement in your "else" branch.

Use

(truth) ? console.log('It is true') : (function(){throw 'It is not true'}());

answered Nov 21, 2012 at 22:43

LWChris

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This makes @Freddie code works but does not explain that ternary need to be an expression and not a statement.

SLaks · Accepted Answer · 2012-11-21 22:29:44Z

2

The conditional operator, like all other operators, can only be used with expressions.

throw x; is a statement, not an expression.

answered Nov 21, 2012 at 22:29

SLaks

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