function sum(list) { var temp = 0; list.forEach(e => temp += e); return temp; } function harmonicMean(list) { var temp = 0; list.forEach(e => temp += 1 / e); return 1 / temp; } function flatten(list, flattable) { return list.reduce( (acc, cur) => acc.concat(cur.constructor.name === flattable ? cur.children : [cur]), []); } export {sum, harmonicMean, flatten }