reduce over an array of arrays code example

Example 1: how to flatten array with reduce in javascript

let flattened = [[0, 1], [2, 3], [4, 5]].reduce(
  function(accumulator, currentValue) {
    return accumulator.concat(currentValue)
  },
  []
)
// flattened is [0, 1, 2, 3, 4, 5]

Example 2: reduce javascript

/* this is our initial value i.e. the starting point*/
const initialValue = 0;

/* numbers array */
const numbers = [5, 10, 15];

/* reducer method that takes in the accumulator and next item */
const reducer = (accumulator, item) => {
  return accumulator + item;
};

/* we give the reduce method our reducer function
  and our initial value */
const total = numbers.reduce(reducer, initialValue)