Suppose we have a function that prints the square of the passed number to the console:
function func(num) {
console.log(num ** 2);
}
Suppose we do not want to display the value to the console, but write it to some variable, like this:
let res = func(3); // now there is 9 in the res variable
To do this, JavaScript has a special instruction
return
, which allows you to specify the
value that the function returns. The word
"returns" means the value that will be written
to the variable if the called function
is assigned to it.
So, let's rewrite our function so that it does not print the result to the console, but returns it to a variable:
function func(num) {
return num ** 2;
}
Let's call our function now, writing its response to a variable:
let res = func(3); // 9 will be written to the variable
After the data is written to a variable, they can, for example, be output to the console:
let res = func(3);
console.log(res); // shows 9
Or you can first somehow change this data, and then print it to the console:
let res = func(3);
res = res + 1;
console.log(res); // shows 10
You can immediately perform some actions with the result of the function before writing to a variable:
let res = func(3) + 1;
console.log(res); // shows 10
Or you can not write the result to a variable, but immediately print it to the console:
console.log(func(3)); // shows 9
You can invoke a function in one expression with different parameters:
let res = func(2) + func(3);
console.log(res); // shows 13
Make a function that takes a number as
a parameter and returns the cube of
that number. Use this function to find
the cube of the number 3
and
store it in the variable res
.
Make such a function that takes a number
as a parameter and returns the square
root of that number. Use this function
to find the root of 3
, then find
the root of 4
. Sum the results
and print them to the console.