Simple example demonstrating the definition and use of a simple generator function.

wayward-generator-example.js

/* generator
 *
 *  takes a chance value, C, an array of objects, and returns a Generator
 *  function that computes a random value, R.  if R < C the Generator returns
 *  nothing, else the Generator returns a random item from the array of
 *  objects.
 *
 *  params:
 *      chance: floating point value between [0,1].
 *      objs:   array of objects to select from.
 */
function generator (chance, objs) {
    /* return the Generator!!!!! mwahahahah */
    return function () {
        if (chance == 0.0 || objs == null) return null;

        var rand = Math.random();       // rand is in [0,1)
        if (rand < chance) return null;
        return objs[Math.floor(rand * objs.length)];    // reuse rand to select random object.
    }
}



/* in the Defs file.
 */

var Defs = {};

Defs.tileTypes = {
    dirt: {
        layer: 4,
        displayName: "Dirt",
        color: "#654423",
        passable: true,
        particles: [120, 80, 45],
        generate: {
            monsters: generator(8.0/100.0, ["bear", "wolf"]);
            items: generator(70.0/600.0, ["poorshovel", "bone", "poorspear"]);
            envItems: generator(0);
            resources: generator(0);
        }
    }
}




/* somewhere in the game where a random monster may spawn */
var monsterSpawn = Defs.tileTypes[tiles[x][y].type].generate.monsters();
if (monsterSpawn != null) {
    /* add monster to tile or wherever a new monster goes */
}

/* repeat for other generated types */