There is a ready-made application for ios - iphone X - Need to adapt to other iphone 5-6-7-8 resolutions?

Question

JavaScript

Hello everybody.
I have a couple of questions for those in the know.
The essence of the question is this. First time I made an app for iphone.
Now I need to understand how to adapt the design that is - for iphone X to other iphone phones, that is, 5-6-7-8,
that is, when I create a file in the same xd and drag all the elements there and press it, the text changes size - it should resize? Or should I leave it as is? - it's just not very clear how it works, in terms of programming in the end. With indents the same story.
+
second.
How to draw files for a programmer?
That is, to export each file separately (without text) as in the layout of the same site? From here the question is why when exporting - x1 x2 x3 and in what format is it better to export? png , svg ?
I would be very grateful for the answer ...
I think this may be useful to many who are just starting to understand this.

Answer 1

I have never seen anything better in my life
https://learn.javascript.ru/
There is really a text, but the presentation of information is gorgeous, each topic with tasks

Answer 2

https://www.youtube.com/results?search_query=javascript

Answer 3

There are also good paid courses, they are great at pumping skills in JS, but it’s probably not allowed to advertise here. The fact is that with a teacher it is better to learn than on your own. You don’t know in advance what you don’t know, so you study only what you encounter, like a blind kitten.

Answer 4

https://m.youtube.com/channel/UCdnFX7mzgup9moXG2fULOog
Favorite channel. It has been abandoned by the author for a long time, but what is there should be enough for a start. I have never met people so motivating to study and explaining well, neither before nor after.
https://m.youtube.com/channel/UCO1cgjhGzsSYb1rsB4bFe4Q
This is where early videos are good.