How do I add multiple key and values to an object from a function in JavaScript?

Question

I have an object

var foo = {
    "prop1" : "value2",
    "prop2" : "value3",
    "prop3" : "value4"
};

and i'd love a way to have a function which would allow one to input multiple key and value pairs at once.

Right now I have this:

function propAndValAdder(){
    for (var i = 0; i < arguments.length; i++) {
        foo[arguments[i]] = [arguments[i + 1]];
    }
}

Is this right?

foo[arguments[i]] = arguments[++i]; (get rid of one set of []) — Jason Fetterly
– Jason Fetterly, Commented Jul 3, 2016 at 16:58

Jason Fetterly · Accepted Answer · 2016-07-03 17:01:14Z

2

You almost got it right: just have to change the loop to add 2 to 'i' (so that you don't add the value as another property, have to skip it) and get rid of the []'s around the value in the assignment line (this is making the value an array which we don't want).

Corrected code:

var foo = {
    "prop1" : "value2",
    "prop2" : "value3",
    "prop3" : "value4"
};

function propAndValAdder(){
    for (var i = 0; i < arguments.length; i+=2) {
        foo[arguments[i]] = arguments[i + 1];
    }
}

propAndValAdder("prop4","value5","prop5","value6");
console.log(foo);

// Object { prop1: "value2", prop2: "value3", prop3: "value4", prop4: "value4", prop5: "value6" }

edited Jul 3, 2016 at 17:01

answered Jul 3, 2016 at 16:45

Jason Fetterly

1821 silver badge12 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Alexis Côté · Accepted Answer · 2016-07-03 17:15:10Z

0

You should pass your information in the parameters and fix your loop.

Corrected version :

   /**
 * Add properties and values to the object
 * @param  {array} arguments An array where even are keys and odd are the values
 * @param  {object} obj       [null] The object to add properties
 * @return {obj}           Return the object but not nessary since it's an object(references)
 */
function propAndValAdder(arguments,obj) {
    if (!obj) obj = {};
    if (arguments.join) //We valid this is an array
        for (var i = 0; i < arguments.length; i += 2)
        obj[arguments[i]] = arguments[i + 1];
    return obj;
}

edited Jul 3, 2016 at 17:15

answered Jul 3, 2016 at 16:24

Alexis Côté

3,6902 gold badges17 silver badges30 bronze badges

2 Comments

JonSG Over a year ago

I think I would conceptually reverse the signature. Probably something more like foo(obj /*, args */) and then in the body capture the array of additional arguments with something like function var args = Array.from(arguments).slice(1)

Jason Fetterly Over a year ago

You have to remove the []'s around [arguments[i + 1]]; or you end up assigning a one-element array

Collectives™ on Stack Overflow

How do I add multiple key and values to an object from a function in JavaScript?

2 Answers 2

Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related