Javascript choose biggest more often than smaller

Question

Javascript choose biggest more often than smaller

I'm busy with nodejs a bit for modding a game, but I'd like to know how to do something like this:

var zombieDirector = 
{
zombieBison = 1
zombieChicken = 2
zombie = 3
skeleton = 3
}

and those names have another var like

var zombieBison = 'Entities/Zombies/zombieBison.cfg'

and now make the Bison spawned rare and skeleton and zombie more often. you get this, where randomZombie equals to 'Entities/Zombies/aZombie.cfg' ks.map.spawnEntity('zombie', randomZombie, 0, 0, 3); I can't get any further than

    var randomZombie = zombieDirector[Math.floor(Math.random() * zombieDirector.length)];

On another note: No JQuery please

Thanks in advance

javascript
node.js

Answer 1

In essence, you're talking about weighted random number generation. A little tricky, if you want to use math, but you can do it with an array, like this:

var choices = [];
for(prop in zombieDirector) {
    for(var i = 0; i<zombieDirector[prop]; i++) {
        choices.push(prop);
    }
}

var choice = choices[Math.floor(Math.random() * choices.length + .5)];

The variable choice will now have a random monster name, weighted based on the number you provide in zombieDirector.