The-Modding-Tree/docs/buyables.md

# Buyables

Buyables are usually things that can be bought multiple times with scaling costs. If you set a respec function,
the player can reset the purchases to get their currency back.

The amount of a buyable owned is a Decimal.
You can get or set the amount of a buyable with getBuyableAmt(layer, id) and setBuyableAmt(layer, id, amt).
You can use buyableEffect(layer, id) to get the current effects of a buyable.

Buyables should be formatted like this:

```js
    buyables: {
        rows: # of rows
        cols: # of columns
        respec() {}, **optional**, implement it to reset things and give back your currency.
                     Having this function makes a respec button appear
        respecText: **optional**, text that appears on the respec button
        11: {
            desc:() => "Blah",
            etc
        }
        etc
    }
```

Features:

- title: **optional**, displayed at the top in a larger font
         It can also be a function that returns updating text.

- cost(): cost for buying the next buyable. Can have an optional argument "x" to calculate the cost of the x+1th object,
          but needs to use "current amount" as a default value for x. Can return an object if there are multiple currencies.
                    
- effect(): **optional**, A function that calculates and returns the current values of bonuses
            of this buyable. Can return a value or an object containing multiple values.

- display(): A function returning everything that should be displayed on the buyable after the title, likely
           including the description, amount bought, cost, and current effect. Can use basic HTML.

- unl(): A function returning a bool to determine if the buyable is visible or not.

- canAfford(): A function returning a bool to determine if you can buy one of the buyables.

- buy(): A function that implements buying one of the buyable. 

- buyMax(): **optional**, A function that implements buying as many of the buyable as possible.

- style: **Optional**, A CSS object, which affects this buyable.

- layer: **Assigned automagically**. It's the same value as the name of this layer, so you can do player[this.layer].points or similar

- id: **Assigned automagically**. It's the id for this buyable.