javascript add random number to a list code example

Example 1: generate random number array javascript from principal array

let numbers = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20],
    generated = [];
for (let i = 0; i < 10; i++)
{
    let random_index;
    while(!random_index)
    {
        let tmp = Math.floor(Math.random() * numbers.length);        
        if( !generated.filter( (g) => numbers[tmp] == g).length )
            random_index = tmp;
    }
    generated.push(numbers[random_index]);
}
console.log(generated);

Example 2: generate an array of random numbers javascript

let numbersArray = [] , max = 100;

for( var i=1; numbersArray.push(i++) < max;);  // numbers = [1,2,3 ... 100]