random number with step

random_with_step.js

function randomWithStep(min, max, step) {
    let prev;
    return function () {
        let current;
        function countFormula() {
            current = min + (step * Math.floor(Math.random()*(max-min)/step));
        }
        do {
            countFormula();
        }
        while (prev === current);
        prev = current;
        return current;
    };
}
let randomNumber = randomWithStep(10, 80, 10);
randomNumber();