# Reduce

Can we get the total price of phones?

Yes, with the reduce function 😏

We are going to calculate the total price of all phones in an array.

First we need an array of phones:

let phones = [
  { model: 'iPhone SE', price: 450.00, color: 'white' },
  { model: 'Samsung S9', price: 900.00, color: 'black' },
  { model: 'LG G7', price: 740.00, color: 'black' }
]

# Procedural way

Let's see the procedural approach first

let totalPhonePrice = 0;

for (let i = 0; i < phones.length; i++) {
  const phone = phones[i];
  totalPhonePrice += phone.price;
}

console.log(totalPhonePrice);

# Functional way

We can use the reduce function:

let totalPhonePrice = _.reduce(phones, (acc, phone) => {
  return acc + phone.price
}, 0)

console.log(totalPhonePrice)

There are 2 things to notice here:

1. acc stands for the accumulator. This is the value accumulated from each item.
2. there is 0 passed as the thrid argument. This is again related to the accumulator and is the initial value / the starting point of the accumulator.

# Summary

The reduce function takes an array and "reduces" / narrows the array to only one value (in our case a number representing the sum of prices).