How to add values from an array of objects using a for loop?

Question

I have an array of objects (cart), the size of which can change, and I need to write a function to add the all the values of a key (itemPrice).

I have tried iterating through the array based on the array length with a for loop, but I don't know how to just add all of the values of that certain key together. I always end up just adding the first value to itself for the length of the array.

My array looks like :

[ { itemName: shoes, itemPrice: 12 }, { itemName: socks, itemPrice: 34 }, { itemName: shorts, itemPrice: 56 }

My for loop looks like:


function total() {
    var total=0;
    for (let i = 0; i <= cart.length; i++) {
        total += cart[i]["itemPrice"] + cart[i]["itemPrice"];
        return total;
    }
}

I expect the output to be 102, but the total is 24. I know why it's 36, it's just adding the first itemPrice to itself 3 times, I just don't know how to get it to add the itemPrice values to each other.

EDIT: Yes, I meant I am getting 24, not 36.

you're returning after first iteration itself, i doubt you're getting 36 you must be getting 24 — Code Maniac
– Code Maniac, Commented Jul 20, 2019 at 18:45

zord · Accepted Answer · 2019-07-20 18:52:06Z

1

You could skip the manual looping and use Array.reduce instead.

const total = cart.reduce((sum, item) => sum + item.itemPrice, 0);

answered Jul 20, 2019 at 18:52

zord

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Syam · Accepted Answer · 2019-07-20 18:51:37Z

0

Answer

var cart = [ { itemName: "shoes", itemPrice: 12 }, { itemName: "socks", itemPrice: 34 }, { itemName: "shorts", itemPrice: 56 }];

function total() {
    var total=0;
    for (let i = 0; i < cart.length; i++) {
        total += cart[i]["itemPrice"] ;//+ cart[i]["itemPrice"];
        // return total;// this is wrong it will exit the loop so you need to remove it
    }
    return total;
}
console.log(total());

answered Jul 20, 2019 at 18:51

Syam

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2 Comments

BenG Over a year ago

Yes, that's it! Thank you, I'm very new to coding and my brain is pretty fried right now from school!

Syam Over a year ago

Welcome to the world for coding :) If it works please mark it as the answer

Ryan Lincoln · Accepted Answer · 2019-07-20 21:23:03Z

0

Take a look at this, for example:

const cart = [{itemName: shoes, itemPrice: 12 }, { itemName: socks, itemPrice: 34 }, { itemName: shorts, itemPrice: 56 }];

const total = () => {
    const checkProp = cart.prototype.map(e => return e.itemPrice).reduce((a, b) =>{return a + b;
    }, 0);
   return checkProp;
}

edited Jul 20, 2019 at 21:23

answered Jul 20, 2019 at 20:32

Ryan Lincoln

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