How does this Recursive function work

Question

function power(base,exponent){
if(exponent==0){
return 1;
}else{
return base* power(base,exponent-1);
}
}
console.log(power(2,3));
// 8
How did JavaScript did the calculation that provided 8 please explain in detail to me

Answer 1

JavaScript done this like: -

1. power(2, 3) , where values 2 and 3 is passed to the function named power.

2. It checks whether exponent is equal to 0 or not. In this case it is equal to 3 and hence the condition becomes false and code in the else block will run.

3. In the else block it returns the expression as base * power(base, exponent-1).

4. In the example above, it can be demonstrated as 2*power(2, 3-1)

5. In the step above, an recursion occurs and power function calls itself.

6.Now in the power function, the values 2 and 2 is passed just as it was passed above. Ex: power(2, 2)

7. Now it again checks the condition that whether the exponent which is 2 in this case is equal to 0 or not and again it evaluates to false and the code in the else block is run.

8. It repeatedly executes just like in a loop and can be demonstrated as power(2,3) = 2 * power(2,2) = 2 * 2 * power(2,1) = 2 * 2 * 2 * power(2,0) = 2 * 2 * 2 * 1.

Answer 2

Base=2
Exponent =3

1st time
(2,3)
Returns (2 * return of (2,3-1))

2nd time
(2,2)
Returns (2* return of (2,2-1))
3rd time
(2,1)
Returns (2*return of (2,1-1))
4th time
(2,0)
Returns 1 as if condition satisfied
Finally
4th return 1
3rd return 2*1
2nd return 2*2
1st return 2*4

We get answer 8
As this time function call 4 times if you cange the number follow the pattern only number of times function call change.

Answer 3

power(2,3) = 2 * power(2,2) = 2 * 2 * power(2,1) = 2 * 2 * 2 * power(2,0) = 2 * 2 * 2 * 1