Generate A Weighted Random Number

Question

I\'m trying to devise a (good) way to choose a random number from a range of possible numbers where each number in the range is given a weight. To put it simply: given the

Answer 1

I have a slotmachine and I used the code below to generate random numbers. In probabilitiesSlotMachine the keys are the output in the slotmachine, and the values represent the weight.

const probabilitiesSlotMachine         = [{0 : 1000}, {1 : 100}, {2 : 50}, {3 : 30}, {4 : 20}, {5 : 10}, {6 : 5}, {7 : 4}, {8 : 2}, {9 : 1}]
var allSlotMachineResults              = []

probabilitiesSlotMachine.forEach(function(obj, index){
    for (var key in obj){
        for (var loop = 0; loop < obj[key]; loop ++){
            allSlotMachineResults.push(key)
        }
    }
});

Now to generate a random output, I use this code:

const random = allSlotMachineResults[Math.floor(Math.random() * allSlotMachineResults.length)]