JavaScript single argument or array

user_8244989 0
Viewed 162

I have a JavaScript function which currently accepts one argument:

foo(country) { ... } and so is used like foo('US')

I need to extend this function to accept one or multiple countries:

foo('US')
foo('US', 'CA', 'UK')
foo(['US', 'CA', 'UK'])

Is any syntax/keyword feature for this? In C# we have a params keyword for this

javascript
4 Answers

Use a gather:

function(...args) {
   // do something with args
}

This is generally considered preferable to using arguments because arguments is a weird case: it isn't truly an array, hence the awkward old idiom you'll still sometimes see:

var args = Array.prototype.slice.call(arguments);
user_37572320

You could take rest parameters ... and flat the array.

function foo(...args) {
    return args.flat();
}

console.log(foo('US'));
console.log(foo('US', 'CA', 'UK'));
console.log(foo(['US', 'CA', 'UK']));

user_14476750

Yes. arguments.

foo(country){
    console.log(arguments)
}

It looks like an array. It's actually an object with numbered keys, but you can still loop through it and get the information you need.

user_40803060

arguments in function plays the same role as params in c#.

function foo() {
  console.log(arguments);
}

foo('a','b','c');
foo('a');

user_82028500
Related