I have a method on my user model to calculate the user's age and return a human readable string. My user's can be between 1 month old and above so the returned string is different depending on if the person is "2 months old" or "1 year old" or "2 years and 3 months old".
I have reviewed few SO posts to come to this solution. Is there anything I am missing? Leap years? Thank you!
def age
dob = self.date_of_birth
# if a date of birth is not nil
if dob != nil
# get current date
now = Date.current
# has person had their birthday yet this year
had_birthday = ((now.month > dob.month || (now.month == dob.month && now.day >= dob.day)) ? true : false)
# if yes then subtract this year from birthday year, if not then also subtract 1 to get how many full years old they are
years = now.year - dob.year - (had_birthday ? 0 : 1)
# get the calendar month difference from birthdya calendar month and today's calendar month. if they have not had their birthdya yet then subtract the difference from 12
months = had_birthday ? now.month - dob.month : 12 - (now.month - dob.month)
# for under 1 year olds
if years == 0
return months > 1 ? months.to_s + " months old" : months.to_s + " month old"
# for 1 year olds
elsif years == 1
return months > 1 ? years.to_s + " year and " + months.to_s + " months old" : years.to_s + " year and " + months.to_s + " month old"
# for older than 1
else
return months > 1 ? years.to_s + " years and " + months.to_s + " months old" : years.to_s + " years and " + months.to_s + " month old"
end
# No date of birth saved so can not calculate age
else
return "No Date of Birth"
end
end
While this may be better posted to a codereview site, I will still give you my thoughts.
You have written a fairly long method for what could be a couple smaller ones.
First, I would write one method that takes the number of years an months and separate that into its own function.
def readable_age(years, months)
# for under 1 year olds
if years == 0
return months > 1 ? months.to_s + " months old" : months.to_s + " month old"
# for 1 year olds
elsif years == 1
return months > 1 ? years.to_s + " year and " + months.to_s + " months old" : years.to_s + " year and " + months.to_s + " month old"
# for older than 1
else
return months > 1 ? years.to_s + " years and " + months.to_s + " months old" : years.to_s + " years and " + months.to_s + " month old"
end
end
Though, if you do not mind adding some dependencies to your project, you can take advantage of the actionview
gem, you can take advantage of the pluralize
function. Something along the lines of
def readable_age(years, months)
year_text = ''
if years != 0
year_text = "#{years} #{pluralize('year', years)} and "
end
"#{year_text}#{pluralize('month', months)} old"
end
Now for your function to calculate the number of years and months.
def age(t)
dob = self.date_of_birth
months = (t.year * 12 + t.month) - (dob.year * 12 + dob.month)
# months / 12 will give the number of years
# months % 12 will give the number of months
readable_age(months / 12, months % 12)
end
EDIT
The reason I am passing a date object into the age
function is to allow you to calculate the the age of a person for a given time stamp. It also makes it easier to test a function if it produces the same result given the same inputs.
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