CODEWITHSUNDEEP
formattingcoffeescriptcode-formatting
Daniel Kaplan
Daniel Kaplan

Reputation: 67360

In CoffeeScript, how should I format a function call that takes an anonymous function and other arguments?

Here's a contrived example I've come up with:

fn = (f, a, b, c)-> alert("#{f() + a + b + c}")

fn((-> "hi"), 1, 2, 3)

I'm wondering what's the suggested way to format that last line? This example is easy to understand, but imagine if the anonymous function (the (-> "hi")) was multi-line and took multiple arguments. This code would become very ugly and start to look lisp-like. 

fn2 = (f, a, b, c)-> alert("#{f(1, 2) + a + b + c}")

fn2(((a, b) -> 
  c = a + b
  c), 1, 2, 3)

This can get pretty nasty. Is there some way I should format this code to make it more readable or is the best advice to name the anonymous function?

I notice a few similar questions asking how to do this. The difference here is I'm asking how to format it.

Upvotes: 1

Views: 68

Answers (2)

hpaulj
hpaulj

Reputation: 231395

In the Coffeescript documentation there's an example with function parameter last

task 'build:parser', 'rebuild the Jison parser', (options) ->
  require 'jison'
  code = require('./lib/grammar').parser.generate()
  dir  = options.output or 'lib'
  fs.writeFile "#{dir}/parser.js", code

The Coffeescript test files have lots of examples with function last

test "multiple semicolon-separated statements in parentheticals", ->
  nonce = {}
  eq nonce, (1; 2; nonce)
  eq nonce, (-> return (1; 2; nonce))()

It's when the function isn't last that you need messier indentation and commas, or extra parenthesis to define the function's boundaries.

Upvotes: 1

epidemian
epidemian

Reputation: 19219

I've seen this style used a couple of times:

fn2 (a, b) -> 
  a + b
, 1, 2, 3

For example, in setTimeout calls:

setTimeout ->
  alert '1 second has passed'
, 1000

But i think in general it's better to separate the parameter function in a variable:

add = (a, b) -> 
  a + b
fn2 add, 1, 2, 3

Or, if it's possible to change the function definition, make the function parameter the last one:

fn2 1, 2, 3, (a, b) ->
  a + b

Upvotes: 2

Related Questions