This is a style guide for the LiveScript programming language.
Use 4 spaces per indentation level, not tabs, not another amount of spaces.
Separate top level class and function definitions with a blank line. Add blank lines as needed for readability.
Don't leave any trailing whitespace.
Don't end your lines with semicolons. Just use a newline. Only use semicolons to separate multiple statements on a single line.
Only have one statement per line.
x = 0
x + y
Align short form switch
statements:
switch
| n <= 0 => []
| empty list => []
| otherwise => [x] ++ take n - 1, xs
Use dashes instead of camel case or underscores to name everything and access existing names.
to-upper-case = -> it.to-upper-case!
Except for class names, use PascalCase for those:
class WidgetThing extends Base
...
true
and false
are preferred over their aliases (yes
, no
, on
, off
), unless the code is much more readable using the alias.
When you can, insert a number comment to specify the units, if it helps readability.
period = 7days * 52weeks
Use single quotes 'hello world'
, except if you need to use string interpolation or have a string with many single quotes in it, in which case use double quotes "hello #var"
.
Use starting and ending whitespace before the first word and after the last, eg.
<[ list of words ]>
not
<[list of words]>
Use a single space after the comma, do not use a space before the comma. Eg.
[x, y, z]
Use @
for this
except when it is stand alone.
Use ::
instead of .prototype.
Array::slice
Singly space operators, except in the case of their use in array access.
x = 1 + 2
list[i-1]
Use and
, or
, etc. over &&
, ||
except when you need the special functionality of &&
, ||
etc. (they do not close implicit calls, unlike and
, or
, etc.)
x = false
y = true
(not) x or y #=> true [(not)(x) || y]
(not) x || y #=> false [(not)(x || y)]
Use isnt
over is not
.
When you can, avoid commas. This means you can leave them out when the preceding item is a non-callable in a list (this includes arguments). However, keep it consistent within a call or a list. Either use commas between all items, or don't use them at all.
[1 2 3]
add-numbers 5 x
[1, x, 3]
Avoid the use of parentheses whenever possible.
Do not use them when calling functions:
Math.pow 2 3
You can use do
instead of parentheses if you are calling against a block for instance:
some-func do
prop: 3
other: 5
Avoid them with chaining, access and logic closes implicit calls:
$ '#content .slider' .find 'a' .slide-up!
You can avoid using them in lists by using a semicolon as a separator when a comma won't work.
[add 2 3; times 2 3]
As mentioned earlier, if you can avoid using commas in the argument list, do so.
If you are calling with no arguments, use a bang call:
func!
Unless you are negating or boolean casting the result, then use ()
as otherwise it looks funny.
!func()
!!func()
Use list.0
instead of list[0]
. Only use the brackets if you need to do some math, e.g. list[i+0].8
As mentioned earlier, align your switch statements.
If you can fit the body of each case on a single line, except for the otherwise
case, use the short form. Otherwise, use the long form.
switch
| even x => x
| even y => y
| otherwise =>
x + y
switch
case f x
blah
...
case g x
asdf
...
default
...
Use default
with the long form.
Use | otherwise =>
with the short form, unless your test cases are very short, in which case you can use | _ =>
switch x
| 2 => 7
| 3 => 8
| 4 => 9
| _ => 10