Javascript array-like objects

Question

hello all. so i have recently started familiarizing myself with array like objects and took notice that they are used to hold properties for objects in games. ie fireball: {name: "fireball", damage=Math.floor(damage+firedmg +Mod), manacost: 3}. Can someone explain how these "values" are used with other array like objects, arrays, variables and your environment? modulization vs hardcodin???