Solution Review: Average of Numbers

function average(testVariable, currentIndex = 0) {
	// Base Case
	if (currentIndex == testVariable.length - 1) { 
		return testVariable[currentIndex]
	}
	
  	// Recursive case1
	// When currentIndex is 0
	if (currentIndex == 0) { 
		return ((testVariable[currentIndex] + average(testVariable, currentIndex + 1)) / testVariable.length)
	}
	
  	// Recursive case2
	// Compute sum 
	return (testVariable[currentIndex] + average(testVariable, currentIndex + 1)) 
}
// Driver code 
array = [10, 2, 3, 4, 8, 0] 
console.log(average(array))