Random number generator without dupes in Javascript?

Question

I need help with writing some code that will create a random number from an array of 12 numbers and print it 9 times without dupes. This has been tough for me to accomplish.

Answer 1

Here is a generic way of getting random numbers between min and max without duplicates:

function inArray(arr, el) {
    for(var i = 0 ; i < arr.length; i++) 
            if(arr[i] == el) return true;
    return false;
}

function getRandomIntNoDuplicates(min, max, DuplicateArr) {
    var RandomInt = Math.floor(Math.random() * (max - min + 1)) + min;
    if (DuplicateArr.length > (max-min) ) return false;  // break endless recursion
    if(!inArray(DuplicateArr, RandomInt)) {
       DuplicateArr.push(RandomInt); 
       return RandomInt;
    }
    return getRandomIntNoDuplicates(min, max, DuplicateArr); //recurse
}

call with:

var duplicates  =[];
for (var i = 1; i <= 6 ; i++) { 
    console.log(getRandomIntNoDuplicates(1,10,duplicates));
}