how to write setTimeout with params by Coffeescript

Question

Please tell me how to write javascript below in coffeescript.

setTimeout(function(){
    something(param);
}, 1000);

how can we add .call('hello') to this – Atul Dec 21 '16 at 11:35 — Atul, Dec 21 '16 at 11:35

score 214 · Accepted Answer · answered Jun 23 '11 at 20:22

I think it's a useful convention for callbacks to come as the last argument to a function. This is usually the case with the Node.js API, for instance. So with that in mind:

delay = (ms, func) -> setTimeout func, ms

delay 1000, -> something param

Granted, this adds the overhead of an extra function call to every setTimeout you make; but in today's JS interpreters, the performance drawback is insignificant unless you're doing it thousands of times per second. (And what are you doing setting thousands of timeouts per second, anyway?)

Of course, a more straightforward approach is to simply name your callback, which tends to produce more readable code anyway (jashkenas is a big fan of this idiom):

callback = -> something param
setTimeout callback, 1000

Great unless you need nested callbacks – Steven Pribilinskiy Dec 24 '14 at 13:12 — Steven Pribilinskiy, Dec 24 '14 at 13:12

score 184 · Answer 2 · edited Feb 12 '13 at 04:40

184

setTimeout ( ->
  something param
), 1000

The parentheses are optional, but starting the line with a comma seemed messy to me.

edited Feb 12 '13 at 04:40

Ry-

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answered Jun 23 '11 at 19:46

Nicholas

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Take out the parens, and have a cup of coffee ,~) – Billy Moon Jun 27 '12 at 01:23
4

Does not compile with the parentheses for me. I had to remove them, start the line with a comma, and it works like a charm. – Jeremy Thille Aug 07 '14 at 13:29
With parentheses you can also do this in one line. – May 13 '15 at 20:47
1

@JeremyThille note that the space in between `setTimeout` and the opening paren is important. The space there means the parentheses are surrounding the closure as the first parameter to setTimeout; if it was directly after the t then coffescript would expect the parentheses to enclose both parameters. – jankins Sep 02 '15 at 21:12

Dirk Smaverson · Answer 3 · 2013-12-13T01:27:28.970

67

setTimeout -> 
  something param
, 1000

edited Dec 13 '13 at 01:27

answered Nov 30 '12 at 19:07

Dirk Smaverson

863
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This is the best if you just want to use an anonymous function. – Alex K Dec 12 '13 at 21:39
also for a named function, setTimeout namedFunc, 5000 – Dirk Smaverson Dec 13 '13 at 01:26
Note that whitespace is important. The call must be spaced exactly as above. If `something param` is on the same line as `setTimeout`, it gets parsed differently. – henrebotha Feb 01 '17 at 10:18

maerics · Answer 4 · 2011-06-23T19:44:49.177

46

This will result in a roughly equivalent translation (thanks @Joel Mueller):

setTimeout (-> something param), 1000

Note that this isn't an exact translation because the anonymous function returns the result of calling something(param) instead of undefined, as in your snippet.

edited Jun 23 '11 at 19:44

answered Jun 23 '11 at 19:39

maerics

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Too many parens/semicolons! This is CoffeeScript, getting rid of excess parens is half the point. `setTimeout (() -> something param), 1000` – Joel Mueller Jun 23 '11 at 19:44
Nicholas makes a good point that the empty parens are also optional. – Joel Mueller Jun 23 '11 at 19:49

score 12 · Answer 5 · answered Jun 09 '13 at 04:34

12

I find this the best method to do the same,

setTimeout (-> alert "hi"), 1000

answered Jun 09 '13 at 04:34

Mahesh Kulkarni

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Ron · Answer 6 · 2013-02-05T14:05:13.037

3

another option:

setTimeout(
    -> something param
    1000
)

edited Feb 05 '13 at 14:05

answered Feb 05 '13 at 11:53

Ron

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how to write setTimeout with params by Coffeescript

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