Throughout the module, our sample code has mostly used variables as names (aliases) for particular values, rather than as variables that change their value over time.
let dollarsInEuro = 1.25; let rublesInDollar = 60; let dollarsCount = 50 * dollarsInEuro; // 62.5 let rublesCount = dollarsCount * rublesInDollar; // 3750 console.log(rublesCount);
const dollarsInEuro = 1.25; const rublesInDollar = 60; const euros = 1000; const dollars = euros * dollarsInEuro; // 1250 const rubles = dollars * rublesInDollar; // 75000 console.log(rubles);
The only change here is syntactical: the keyword
let has been replaced by
const. Now if we try to change any constant, we get an error message. Otherwise, it behaves the same way as a variable.
const pi = 3.14; pi = 5; // TypeError: Assignment to constant variable.
Constants make it a lot easier to analyze; when we encounter a constant, it's obvious right away that its value always stays the same. With constants, we don't need to worry about when they were written. With variables, however, we can't be certain of their value and have to analyze all the code to figure out how they may have changed.
Variables are essential only in one case (in all others, we can do without them for sure) and that's when we're dealing with loops. We'll get to that point later.
From now on, we will stick to constants and use variables only when it's inevitable.
Create a constant called
army, assign it
the white walkers value, and print it.
The exercise doesn't pass checking. What to do? 😶
If you've reached a deadlock it's time to ask your question in the «Discussions». How ask a question correctly:
- Be sure to attach the test output, without it it's almost impossible to figure out what went wrong, even if you show your code. It's complicated for developers to execute code in their heads, but having a mistake before their eyes most probably will be helpful.
In my environment the code works, but not here 🤨
Tests are designed so that they test the solution in different ways and against different data. Often the solution works with one kind of input data but doesn't work with others. Check the «Tests» tab to figure this out, you can find hints at the error output.
My code is different from the teacher's one 🤔
It's fine. 🙆 One task in programming can be solved in many different ways. If your code passed all tests, it complies with the task conditions.
In some rare cases, the solution may be adjusted to the tests, but this can be seen immediately.
I've read the lessons but nothing is clear 🙄
It's hard to make educational materials that will suit everyone. We do our best but there is always something to improve. If you see a material that is not clear to you, describe the problem in “Discussions”. It will be great if you'll write unclear points in the question form. Usually, we need a few days for corrections.
By the way, you can participate in courses improvement. There is a link below to the lessons course code which you can edit right in your browser.