javascript mongoose Most Efficient between findindex and updateOne

I am updating an array inside a field but I am looking for which one is the most method efficient with respect to system resource and speed between.

method 1. 
    {arrayFilters:[{'first.dept_id': thisidthedeptid},      <---array filter to get specific data
                   {'second.dept_id': thisidthedeptid},]}


method 2.
var contactIdx =>
var employmentIdx = usermodel.employment_detail.findIndex(x=>
            x.dept_id==thisidthedeptid)[contactIdx].state = 'California'
usermodel.employment_detail[employmentIdx].employment_date =

Please this is not for a debate or some thing like that. I want to know which one I should stick to. And please state reasons for it. I could not run a test on my system