Recursive functions Js

Question

I have numbers array, through my_number function I create a random numer, if it already exist in the array, I call the function again and create a new random number, if it is not in the array I send it to it through push.

Unfortunately it sems to send all numbers again and again until browser crashes.

How could I fix this.

Thanks for your help

var numbers = [1,2,3,4,5];

function mainFunction(){
    function my_number(){
        var randomNumber = Math.floor((Math.random()*7)+1);
        for(let i=0; i<numbers.length; i++){
            if(numbers[i] === randomNumber){
                my_number();
            }else{
                numbers.push(randomNumber);
            }
        }
    }
    
    my_number();
}

mainFunction();

Answer 1

In my_number function, you have called my_number again inside for-loop and it is needed to call my_number function with the result of the for-loop.

So it is needed to get the result if the randomNumber has existed or not through for-loop and based on that, you need to decide to call the function again or not.

1. Preferred Way

   const numbers = [1,2,3,4,5];
   
   function mainFunction(){
     function my_number(){
       const randomNumber = Math.floor((Math.random()*7)+1);
       const isExisted = numbers.some((item) => item === randomNumber);
       if (isExisted) {
         my_number();
       } else {
         numbers.push(randomNumber);
       }
     }
     my_number();
   }
   
   mainFunction();
   console.log(numbers);

2. Regarding your CodeBase.

const numbers = [1,2,3,4,5];

function mainFunction(){
  function my_number(){
    const randomNumber = Math.floor((Math.random()*7)+1);
    let isExisted = false;
    for (let index = 0; index < numbers.length; index ++) {
      if (numbers[index] === randomNumber) {
        isExisted = true;
        break;
      }
    }
    if (isExisted) {
      my_number();
    } else {
      numbers.push(randomNumber);
    }
  }
  my_number();
}

mainFunction();
console.log(numbers);

Answer 2

There are quite a few problems with the code.

• As Pointy pointed out, i should be numbers[i] to compare the array element instead of the index.
• You have a function definition inside another function, which is fine, but the only thing the outer function does is call the inner function, so it's redundant.
• numbers.push(randomNumber) should be done outside the for loop because it would otherwise only check if randomNumber matches the first element and ignores the rest.
• After the call to my_number in the for loop, you need a return statement to prevent the loop from continuing after detecting failure.

var numbers = [1,2,3,4,5];

function my_number() {
    var randomNumber = Math.floor((Math.random() * 7) + 1);
    for(let i = 0; i < numbers.length; i++){
        if (numbers[i] === randomNumber){
            my_number();
            return;
        }
    }
    numbers.push(randomNumber);
}

my_number();

console.log(numbers);