Recursion is a technique to iterate over an operation by having a function call itself repeatedly until it arrives at a result.
function add(number) {
if (number <= 0) {
return 0;
} else {
return number + add(number - 1);
}
}
add(3) => 3 + add(2)
3 + 2 + add(1)
3 + 2 + 1 + add(0)
3 + 2 + 1 + 0 = 6
Example of a recursive function:
The following function calculates the sum of all the elements in an array by using recursion:
function computeSum(arr){
if(arr.length === 1){
return arr[0];
}
else{
return arr.pop() + computeSum(arr);
}
}
computeSum([7, 8, 9, 99]); // Returns 123
