source: ps/trunk/binaries/data/mods/public/simulation/helpers/WeightedList.js@ 25276

function WeightedList()
{
    this.elements = new Map();
    this.totalWeight = 0;
};

WeightedList.prototype.length = function()
{
    return this.elements.size;
};

WeightedList.prototype.push = function(item, weight = 1)
{
    this.elements.set(item, weight);
    this.totalWeight += weight;
};

WeightedList.prototype.remove = function(item)
{
    const weight = this.elements.get(item);
    if (weight)
        this.totalWeight -= weight;
    this.elements.delete(item);
};

WeightedList.prototype.randomItem = function()
{
    const targetWeight = randFloat(0, this.totalWeight);
    let cumulativeWeight = 0;
    for (let [item, weight] of this.elements)
    {
        cumulativeWeight += weight;
        if (cumulativeWeight >= targetWeight)
            return item;
    }
    return undefined;
};

Engine.RegisterGlobal("WeightedList", WeightedList);