How to use `reduce()` method

You can use the reduce() method to reduce an array to a single value. The reduce() method executes a reducer function (that you provide) on each element of the array, resulting in a single output value.

Syntax §

array.reduce((accumulator, currentValue) => {
  // ...
}, initialValue);

Example §

You can use the reduce() method to sum all the numbers in an array.

const numbers = [1, 2, 3, 4, 5, 6];
 
const sum = numbers.reduce((accumulator, currentValue) => {
  return accumulator + currentValue;
}, 0);
 
console.log(numbers); // [1, 2, 3, 4, 5, 6]
console.log(sum); // 21