Write, simplify

Remember, we talked about the fact that a function can return its result and placed a function call directly into an expression? Like that:

console.log('We’ll get ' + calculateMiles(4125) + ' miles for the flight');

And now let’s write the code more competently.

Once a function returns a value that can be used somewhere else (place into a line, add to a mathematical operation), why not write the result of this function into a variable and then use it? This way the code will be easier to read and edit.

Imagine a large program with hundreds of lines of code. You use the function call several times inside some expressions and the program works. And then you understand that you need to call the same function with other arguments, and you or your colleague have to look across the entire code for these function calls and fix them. And if you miss something, the program will not work correctly.