Array Reduce Examples

array-reduce.js

const items = [1, 2, 3, 4, 5];

/* Example when we return only a string value. */
const concatString = items.reduce((string, item) => `${string}${item},`, "");

/* Example when we return the first odd number. */
const firstOddValue = items.reduce((value, item) => {
  if (value == null && item % 2 === 0) {
    return item;
  }

  return value
}, null);

console.log(concatString);
console.log(firstOddValue);