Recursive function in JavaScript

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Recursive function in JavaScript

What is recursion?
This function is invoked in the body of the function. It is a call mode, a logic-based expression.

== Recursion consume large amounts of memory, rarely used in the actual development ==

Note: Recursive most important is the termination condition.

Recursive calculation of the factorial of n

function acc(n){
        if(n<=1){
            return 1;
        }else{
                return n*acc(n-1)
            }
    }
    console.log(acc(4));

Calculated here are 4 factorial; from the beginning, return 1; and 2, return 2 by acc (1) - 1 is multiplied by 2; ... sequentially

The use of recursion Fibonacci number (1,1,2,3,5,8,13,21,34,55,89 ...)

var m=1;
    while(true){
        function fiber(m){
            if(m-1==0 || m-2==0){
                return 1;
            }else{
                    return (fiber(m-1)+fiber(m-2));
                }
        }
        console.log(fiber(m));
        m++;
    }

The characteristics of the Fibonacci columns, m represents the number of columns of items, we can get the fiber (m) = fiber (m -2) + fiber (m-1);
it requires: m> 2; so I use to if () {} else {} a branched structure.
When m = 1, m = 2, return 1;
utilized herein made of a while loop, a digital output in sequence for each item.

We do not understand can be calculated from recursive 1 + 2 + 3 + 4 + 5 =? Start;

function fn(n){
    if(n<=1){
        return 1;
    }else{
        return n+fn(n-1)
    }
}
console.log(fn(5))

Where n represents both the first several, and they represent a corresponding entry in the digital
value of the return current item n with the former one.