js reducer sum code example

Example 1: javascript reduce sum

let nums = [1, 2, 3];

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

Example 2: reduce javascript

//note idx and sourceArray are optional
const sum = array.reduce((accumulator, element[, idx[, sourceArray]]) => {
	//arbitrary example of why idx might be needed
	return accumulator + idx * 2 + element 
}, 0);