common function that accept all argument in javaScript

Question

often time I have this pattern problem in javascript. I have an add function

function add(a, b){ return a + b; }

then I can do add(1,2) //3

but what if I want to pass in any length of arguments?

I can't do freely add(1,2,3,4). or add(something,something,something). If I want I have to write another add function that accept 4 and 3 arguments.

I know I can use loop them up by loop but how to pass any number of argument to a function in js?

So loop over the arguments https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/arguments — epascarello, Dec 06 '16 at 13:45

Mahi · Answer 1 · 2016-12-06T13:46:07.730

1

you can use arguments property .

function add(){
  var sum=0;
  for (var key in arguments)
    sum=sum+arguments[key];
 return sum;
}
console.log(add(1,2,3,7));

edited Dec 06 '16 at 13:46

answered Dec 06 '16 at 13:45

Mahi

1,707
11
22

1

why a for in loop? – epascarello Dec 06 '16 at 13:45
we use for in loop to get the key of object. – Mahi Dec 06 '16 at 13:47
But it is not an object, it is an array like structure. – epascarello Dec 06 '16 at 13:47
@epascarello we can use arguments.length too – Mahi Dec 06 '16 at 13:47
I guess `arguments` is an array like object but is not an array so you will either have to convert it to array or use for..in – Rajesh Dec 06 '16 at 13:48
@epascarello whatever it has object or array .but we can use for in loop for both object or array . – Mahi Dec 06 '16 at 13:49
arguments is a reserved words in javascript? – Jessie Emerson Dec 06 '16 at 13:52
a native for loop will be much cleaner in my opinion. – Jessie Emerson Dec 06 '16 at 13:53
@JessieEmerson And `for..in` is not native? – Rajesh Dec 06 '16 at 13:53
it is but it's newer than the traditional for loop :P – Jessie Emerson Dec 06 '16 at 13:55
@JessieEmerson its supported by [IE6](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in#Browser_compatibility). You cannot go to support before that. Also, `for..in` is the ideal way to loop over objects. **Remember, `arguments` is not an Array** – Rajesh Dec 06 '16 at 13:58
why not use native for loop? it's faster than for in. – Jessie Emerson Dec 06 '16 at 14:20

score 1 · Answer 2 · edited Jun 20 '20 at 09:12

1

You can loop over arguments and add values

ES6

function add(){
  return Array.from(arguments).reduce((p,c)=>p+= !isNaN(c)? +c : 0, 0)
}

console.log(add(1,2,3,4,5))
console.log(add(1,2,3,'a', 7))

ES5

function add(){
  return [].slice.call(arguments).reduce(function(p,c){
    p+= !isNaN(c)? +c : 0;
    return p;
  }, 0)
}

console.log(add(1,2,3,4,5))
console.log(add(1,2,3,'a', 7))

edited Jun 20 '20 at 09:12

Community

1
1

answered Dec 06 '16 at 13:46

Rajesh

24,354
5
48
79

(With the caveat that you'll need babel or a polyfill for IE and earlier browsers.) – Dave Newton Dec 06 '16 at 13:47
Oh @DaveNewton would using `[].slice.call(arguments).reduce(...)` make you happy? ;) – epascarello Dec 06 '16 at 13:49
@rajesh why go into ocean when OP asked only one glass of water . – Mahi Dec 06 '16 at 13:51
@DaveNewton I have added handling for both. – Rajesh Dec 06 '16 at 13:51
@epascarello Delirious! – Dave Newton Dec 06 '16 at 13:52
@Mahi My bad. Are you pointing about `!isNaN`? – Rajesh Dec 06 '16 at 13:52
this is overkilled – Jessie Emerson Dec 06 '16 at 13:52
@JessieEmerson My bad! CS player, bad habit. – Rajesh Dec 06 '16 at 13:55

common function that accept all argument in javaScript

2 Answers2

ES6

ES5