Omitting the second expression when using the if-else shorthand

Question

Can I write the if else shorthand without the else    var x 1   x  2   dosomething     doNothingButContinueCode         I ve noticed putting null for the else works  but I have no idea why or if that s a good idea     Edit  Some of you seem bemused why I d bother trying this  Rest assured it s purely out of curiosity  I like messing around with JavaScript

User · Accepted Answer

This is also an option   x  2  amp  amp  dosomething      dosomething   will only be called if x  2 is evaluated to true  This is called Short-circuiting   It is not commonly used in cases like this and you really shouldn t write code like this  I encourage this simpler approach   if x  2  dosomething      You should write readable code at all times  if you are worried about file size  just create a minified version of it with help of one of the many JS compressors   e g Google s Closure Compiler

User · Answer

Another option   x     2   doSomething     void 0

User · Answer

Probably shortest  based on OR operator and its precedence   x-2  dosomething      x000D   x000D  let x 1  y 2  x000D  let dosomething   s  gt console log s    x000D   x000D  x-2  dosomething  x do something    x000D  y-2  dosomething  y do something    x000D   x000D   x000D

User · Answer

Tiny addition to this very old thread    If your e evaluating an expression inside a for while loop with a ternary operator  and want to continue or break as a result - you re gonna have a problem because both continue amp break aren t expressions  they re statements without any value   This will produce Uncaught SyntaxError  Unexpected token continue   for  const item of myArray          item value   break   continue       If you really want a one-liner that returns a statement  you can use this instead     for  const item of myArray          if  item value  break  else continue         P S - This code might raise some eyebrows  Just saying

User · Answer

If you re not doing the else  why not do   if  x  2  doSomething

User · Answer

Using null is fine for one of the branches of a ternary expression  And a ternary expression  is fine as a statement in Javascript   As a matter of style  though  if you have in mind invoking a procedure  it s clearer to write this using if  else   if  x  2  doSomething  else doSomethingElse   or  in your case   if  x  2  doSomething

User · Answer

Technically  putting null or 0  or just some random value there works  since you are not using the return value   However  why are you using this construct instead of the if construct  It is less obvious what you are trying to do when you write code this way  as you may confuse people with the no-op  null in your case

User · Answer

What you have is a fairly unusual use of the ternary operator  Usually it is used as an expression  not a statement  inside of some other operation  e g    var y    x    2    yes     no      So  for readability  because what you are doing is unusual   and because it avoids the  else  that you don t want  I would suggest   if  x  2  doSomething

[javascript] Omitting the second expression when using the if-else shorthand

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