reduce

reduce() is an array method that works by applying an accumulator to each element in the array in order to simplify it into a single value.

Example

[1,2,3].reduce(function (accumulator, current) {
  return accumulator + current;
});

// should return 6

You may also pass an initial value for instance:

[1,2,3].reduce(function (accumulator, current) {
  return accumulator + current;
}, 10);

// should return 16

The code found on this repository is an implementation of the reduce method. Furthermore, it can be used as a polyfill.