Shorthand if else statement Javascript

Question

I m wondering if there s a shorter way to write this   var x   1  if y    undefined  x   y    I initially tried x   y    1  but that didn t work  What s the correct way to go about this

User · Accepted Answer

var x   y     undefined   y   1    Note that var x   y    1  would assign 1 for any case where y is falsy  e g  false  0       which may be why it  didn t work  for you  Also  if y is a global variable  if it s truly not defined you may run into an error unless you access it as window y     As vol7ron suggests in the comments  you can also use typeof to avoid the need to refer to global vars as window  lt name gt    var x   typeof y     undefined    y   1

User · Answer

Here is a way to do it that works  but may not be best practise for any language really   var x y  x  something   y 1  undefined     y     x   y     alternatively  undefined     y  amp  amp   x   y

User · Answer

Appears you are having  y  default to 1  An arrow function would be useful in 2020   let x    y   1    gt    insert operation with y here   Let  x  be a function where  y  is a parameter which would be assigned a default to  1  if it is some null or undefined value  then return some operation with y

User · Answer

Other way is using short-circuit   x    typeof y      undefined    amp  amp  y    1  Although I myself think that ternary is more readable

User · Answer

You can try if else this shorthand method      Syntax if condition    else condition     Example let oldStr       let newStr   oldStr     Updated Value   console log newStr      Updated Value     Example 2 let num1   2  let num2   num1    3  console log num2       2  cause num1 is a truthy

User · Answer

y    y    undefined    y   x    The parenthesis are not necessary  I just add them because I think it s easier to read this way

User · Answer

Another way to write it shortly  bePlanVar       bePlanVar    false        is equivalent to  bePlanVar    bePlanVar    false    true   false      and   if  bePlanVar    false        bePlanVar   true    else       bePlanVar   false

[javascript] Shorthand if/else statement Javascript

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