What is the name of the method that we can use to accumulate the sum of an array entries? code example

Example 1: javascript reduce sum

let nums = [1, 2, 3];

nums.reduce((curr, next) => curr + next);

Example 2: reduce method in javascript array of bjects

var arr = [{x:1}, {x:2}, {x:4}];
arr.reduce(function (acc, obj) { return acc + obj.x; }, 0); // 7
console.log(arr);