Global variable accessible from all pages

It’s not possible to have a global constant string or so?
If i have a const in a page (const string test = “test”) then i is the same amount of code (or even more) to call for that const.
Like - if i store the string test in the session data - then i still have to write session.get(“test”) to get that test string. There’s no code saved and in the end it’s actually more code because i have to declare a variable and also get the data via a identifier…

We need something like a global variable - like you define it in the site as global const string test = “jfjfjaofijaofj”; and then use it on all pages with just calling the test variable…