# Ternary operation in CoffeeScript

evfwcqcg Source

I need to set value to `a` that depends on a condition.

What is the shortest way to do this with CoffeeScript?

E.g. this is how I'd do it in JavaScript:

``````a = true  ? 5 : 10  # => a = 5
a = false ? 5 : 10  # => a = 10
``````
javascriptcoffeescriptternary-operator

answered 6 years ago loganfsmyth #1

Since everything is an expression, and thus results in a value, you can just use `if/else`.

``````a = if true then 5 else 10
a = if false then 5 else 10
``````

You can see more about expression examples here.

answered 6 years ago Paul Oliver #2

``````a = if true then 5 else 10
a = if false then 5 else 10
``````

See documentation.

answered 5 years ago Alexander Senko #3

In almost any language this should work instead:

``````a = true  && 5 || 10
a = false && 5 || 10
``````

answered 3 years ago Alinex #4

You may also write it in two statements if it mostly is true use:

``````a = 5
a = 10 if false
``````

Or use a switch statement if you need more possibilities:

``````a = switch x
when true then 5
when false then 10
``````

With a boolean it may be oversized but i find it very readable.

answered 2 years ago Max Peng #5

Coffeescript doesn't support javascript ternary operator. Here is the reason from the coffeescript author:

I love ternary operators just as much as the next guy (probably a bit more, actually), but the syntax isn't what makes them good -- they're great because they can fit an if/else on a single line as an expression.

Their syntax is just another bit of mystifying magic to memorize, with no analogue to anything else in the language. The result being equal, I'd much rather have `if/elses` always look the same (and always be compiled into an expression).

So, in CoffeeScript, even multi-line ifs will compile into ternaries when appropriate, as will if statements without an else clause:

``````if sunny
go_outside()
else

if sunny then go_outside() else read_a_book()
``````

Both become ternaries, both can be used as expressions. It's consistent, and there's no new syntax to learn. So, thanks for the suggestion, but I'm closing this ticket as "wontfix".

Please refer to the github issue: https://github.com/jashkenas/coffeescript/issues/11#issuecomment-97802

answered 11 months ago quotesBro #6

``````a = if b # a depends on b
then 5   # b is true
else 10  # b is false
``````

answered 1 week ago Эд Лесничий #7

`CoffeeScript` has no ternary operator. That's what the docs say.

You can still use a syntax like

``````a = true then 5 else 10
``````

It's way much clearer.