JavaScript generate random number except some values

Question

I\'m generating random numbers from 1 to 20 by calling generateRandom(). How can I exclude some values, say 8 and 15?

function generateRandom(mi         


        

Answer 1

You could take an offset for random values greater or equal than zerow ith a sorted (ascending) array and return a sum with adjusted random value.

const
    getRandomWithoutZero = (lower, upper, gaps) => () => {
        const r = Math.floor(Math.random() * (upper - lower + 1 - gaps.length) + lower);
        return gaps.reduce((s, g) => s + (s >= g), r);
    },
    random = getRandomWithoutZero(-9, 9, [-3, 0, 4]),
    count = {};

for (let i = 0; i < 1.6e6; i++) {
    const r = random();
    count[r] = (count[r] || 0) + 1;
}

console.log(count);

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