Generate random number in increments of X in Javascript not working

You could divide by the wanted delta and multiply the random value by it to get a wanted gap.

function getRndInteger(min, max, delta) {
    return delta * Math.floor(Math.random() * (max - min) / delta + min / delta);
}

console.log(...Array.from({ length: 10 }, getRndInteger.bind(null, 50, 500, 50)));

Try this:

function getRndInteger(min, max) {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min + 1)) + min;
}
var x = 1;
var max = 1000;
for(i=0;i<=5;i++){
  x = getRndInteger(x,max)
  console.log(x);
}

I'm not sure to have understand well. This function generate numbers from min and max with a specific step:

function getRndInteger(min, max, step) {
  const range = (max - min) / step;
  return Math.floor(Math.random() * range) * step + min  
}
console.log(getRndInteger(50, 500, 10))

is it what you need?

As described on the Mozilla Developer Site, use this approach:

/**
 * Returns a random number between min (inclusive) and max (exclusive)
 */
function getRandomArbitrary(min, max) {
    return Math.random() * (max - min) + min;
}

/**
 * Returns a random integer between min (inclusive) and max (inclusive).
 * The value is no lower than min (or the next integer greater than min
 * if min isn't an integer) and no greater than max (or the next integer
 * lower than max if max isn't an integer).
 * Using Math.round() will give you a non-uniform distribution!
 */
function getRandomInt(min, max) {
    min = Math.ceil(min);
    max = Math.floor(max);
    return Math.floor(Math.random() * (max - min + 1)) + min;
}

After you have a random number in your range, you can then round it to the desired increment.

Math.ceil(number / 100) * 100 // rounds to next 100

function random(min, max) {
  // get max multiplier 
  let totalSteps = Math.floor(max / min);

  // get a random multiplier between 1 and max multiplier
  let randomStep = Math.floor(Math.random() * totalSteps) + 1;

  // multiply by min and return
  return randomStep * min;
}