For me, lines of code per day varies depending on what is being done and how.
If it's a meaty problem that is not well understood, or a language or framework I'm unfamiliar with, or I sense the situation is complex enough that an early bad decision could lead to unforeseen troubles later (and I should tread carefully), very few or no lines are written during the day.
On the other hand, if it is similar to a thing I have done many times before, and I'm comfortable with the problem, the language and framework then there is much less time thinking and StackOverflowing and I can go at nearly typing speed. (Likewise, if the code is quick "one of" type things for tests or throwaway stuff). More than several hundred lines of code a day (JS or Python) in cases like these is very achievable.
This doesn't count things like html templates, css etc (although sometime that take a bit of thought as well).
If it's a meaty problem that is not well understood, or a language or framework I'm unfamiliar with, or I sense the situation is complex enough that an early bad decision could lead to unforeseen troubles later (and I should tread carefully), very few or no lines are written during the day.
On the other hand, if it is similar to a thing I have done many times before, and I'm comfortable with the problem, the language and framework then there is much less time thinking and StackOverflowing and I can go at nearly typing speed. (Likewise, if the code is quick "one of" type things for tests or throwaway stuff). More than several hundred lines of code a day (JS or Python) in cases like these is very achievable.
This doesn't count things like html templates, css etc (although sometime that take a bit of thought as well).