Calling function with a varying number of arguments (JS)

Question

Anyone knows how to do it (using ES5)? Hello.

Found similar questions in the C++ and C sections, but not in the Javascript one.

var array = [1, 2, 3, 4, 5];
 
//single argument
console.log(array[0]);
 
//dynamic arguments
var item;
for (var i in array) {
 item = array[i];
 console.log("test", item);
 //same as
 //console.log("test", 0);
 //console.log("test", 1);
 //...
}

//Objective: console.log("test", 1, 2, 3, 4, 5);
/*var obj = {};
for (var key in array) {
 obj[key] = array[key];
}
console.log("test", obj[0], obj[1], obj[2], obj[3], obj[4]);
*/
console.log("test", array[0], array[1], array[2], array[3], array[4]);
//need to know the no. of items

What exactly do you want to achieve? What function need to accept varying number of arguments? What arguments list and how do it varies? — MysterX, Nov 28 '17 at 09:59
Just pass the array directly to whatever number of arguments required! — Aakash Verma, Nov 28 '17 at 10:02

Suren Srapyan · Accepted Answer · 2017-11-28T10:05:47.207

3

You need the spread operator. It destructures your array and passes the items as separate variables.

var array = [1, 2, 3, 4, 5];
 
console.log("test", ...array); // ES6 and higher
console.log.apply(console, ["test"].concat(array)); // ES5

edited Nov 28 '17 at 10:05

answered Nov 28 '17 at 09:59

Suren Srapyan

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If the spread operator isn't available then something like: console.log.apply(console, ["test"].concat(array)) – kmdm Nov 28 '17 at 10:00
Answer apart, I still don't know how the question made sense to you :) – blueren Nov 28 '17 at 10:02
Yeah; can use the ES5 version of spread: https://github.com/addyosmani/es6-equivalents-in-es5#spread-operator Thanks. – Ramsing Nadeem Nov 28 '17 at 10:02
My apology; I forgot. Thanks again. – Ramsing Nadeem Nov 29 '17 at 06:30

Calling function with a varying number of arguments (JS)

1 Answers1