javascript reduce with a sum es6 code example

Example 1: 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);

Example 2: javascript, reduce

const myReduce = myArray.reduce((acc, item) => {
	acc += item
})