JavaScript reduce throwing error for more than two items

Question

I have this array:

const arr = [
  { someProp: [{ amount: 10 }]},
  { someProp: [{ amount: 12 }]},
];

and then this reduce fn:

con         


        

Answer 1

Actually you need only to return the accumulator + the new value.

You want to begin with 0 i guess so you need to add 0 as second parameter

const arr =
    [
      { someProp: [{ amount: 10 }]},
      { someProp: [{ amount: 12 }]},
      { someProp: [{ amount: 12 }]},
    ];
    
const sum = arr.reduce((acc, item) => item.someProp[0].amount + acc, 0);

console.log(sum);

If you want it more spicy here with destructuring

const arr =
    [
      { someProp: [{ amount: 10 }]},
      { someProp: [{ amount: 12 }]},
      { someProp: [{ amount: 12 }]},
    ];
    
const sum = arr.reduce((acc, { someProp: [{ amount }] }) => amount + acc, 0);

console.log(sum);