JavaScript: Calling a function with a variable number of arguments

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This card describes how to pass an array with multiple element to a JavaScript function, so that the first array element becomes the first function argument, the second element becomes the second argument, etc.

Note how this is different from passing the entire array as the first argument. Compare these two different ways of calling fun() in Ruby:

# Ruby
array = [1, 2, 3]
fun(array)  # same as fun([1, 2, 3]) (1 argument)
fun(*array) # same as fun(1, 2, 3)   (3 arguments)

Depending on your culture the spreading of array elements into multiple argument slots is called "splat args" or "varargs" or "spread args" or "rest operator".

EcmaScript 6 (ES6)

console.log(...array)

EcmaScript 5 (ES5)

var array = [1, 2, 3]
console.log.apply(console, array)

CoffeeScript

console.log(array...)
Henning Koch
Last edit
Michael Leimstädtner
Keywords
varargs, splat, rest, arguments
License
Source code in this card is licensed under the MIT License.
Posted by Henning Koch to makandra dev (2014-06-29 19:06)