Looking at this CoffeeScript tutorial : http://jashkenas.github.com/coffee-script/
I don't quite see what the Splats is for. What is this construction? Where does it come from (historically)
The term "splat operator" comes from Ruby, where the * character (sometimes called the "splat"—see the Jargon File entry) is used to indicate that an entry in an argument list should "soak up" a list of arguments.
CoffeeScript is a lightweight language that compiles into JavaScript. It provides simple and easy to learn syntax avoiding the complex syntax of JavaScript.
"Easy to read", "Faster to write" and "Syntactic sugar" are the key factors why developers consider CoffeeScript; whereas "Can be used on frontend/backend", "It's everywhere" and "Lots of great frameworks" are the primary reasons why JavaScript is favored.
CoffeeScript is a programming language that compiles to JavaScript. It adds syntactic sugar inspired by Ruby, Python, and Haskell in an effort to enhance JavaScript's brevity and readability. Specific additional features include list comprehension and destructuring assignment.
The term "splat operator" comes from Ruby, where the *
character (sometimes called the "splat"—see the Jargon File entry) is used to indicate that an entry in an argument list should "soak up" a list of arguments.
CoffeeScript adopted Ruby-style splats very early on (see issue 16), but at Douglas Crockford's suggestion, the syntax was changed from *x
to x...
a couple of weeks later (see issue 45). Nevertheless, CoffeeScripters still refer to the syntax as the "splat" or "splat operator."
As to what they actually do, splats slice the arguments
object in such a way that the splatted argument becomes an array of all "extra" arguments. The most trivial example is
(args...) ->
In this case, args
will simply be an array copy of arguments
. Splatted arguments can come either before, after, or between standard arguments:
(first, rest...) -> (rest..., last) -> (first, rest..., last) ->
In the first two cases, if the function receives 0-1 arguments, rest
will be an empty array. In the last case, the function needs to receive more than 2 arguments for rest
to be non-empty.
Since JavaScript doesn't allow multiple signatures for functions with the same name (the way C and Java do), splats are a huge time-saver for dealing with varying numbers of arguments.
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