JAVASCRIPT

lodash sum array of objects

const data = {"salary":[{"bills":[{"electricity":300,"milk":500},{"electricity":240,"milk":200},{"electricity":800,"milk":900}]}]}

const result = _.sumBy(data.salary, ({ bills }) => _.sumBy(bills, 'milk'))

console.log(result)

lodash sum of two array elements

_.reduce(keys, function(result, key, index){
    result[key] = result[key] ? result[key] + values[index] : values[index];
    return result;
}, {})