The main way to add content is through creating layers. You can either add a layer directly in the layers object in [layerSupport.js](/js/layerSupport.js), or declare it in another file and register it by calling `addLayer(layername, layerdata)`. There is an example layer registration in [layers.js](/js/layers.js) showing the recommended method. It is just an example and can be freely deleted. You can also use it as a reference or a base for your own layers.
The first thing you need to do is fill out the modInfo object at the top of [mod.js](/js/mod.js) to set your mod's name, ID (a string), and other information. A unique modId will prevent your mod's saves from conflicting with other mods. Note that changing this after people have started playing will reset their saves.
Most of the time, you won't need to dive deep into the code to create things, but you still can if you really want to, for example to add new Vue components in [v.js](/js/v.js).
The Modding Tree uses [break\_eternity.js](https://github.com/Patashu/break_eternity.js) to store large values. This means that many numbers are `Decimal` objects, and must be treated differently. For example, you have to use `new Decimal(x)` to create a `Decimal` value instead of a plain number, and perform operations on them by calling functions. e.g, instead of `x = x + y`, use `x = x.add(y)`. Keep in mind this also applies to comparison operators, which should be replaced with calling the `.gt`, `.gte`, `.lt`, `.lte`, `.eq`, and `.neq` functions. See the [break\_eternity.js](https://github.com/Patashu/break_eternity.js) docs for more details on working with `Decimal` values.
Almost all values can be either a constant value, or a dynamic value. Dynamic values are defined by putting a function that returns what the value should be at any given time.
- [Custom Tab Layouts](custom-tab-layouts.md): An optional way to give your tabs a different layout. You can even create entirely new components to use.
- [Buyables](buyables.md): Create rebuyable upgrades for your layer (with the option to make them respec-able). Can be used to make Enhancers or Space Buildings.
- [Clickables](clickables.md): A more generalized variant of buyables, for any kind of thing that is sometimes clickable. Between these and Buyables, you can do just about anything.
- [Bars](bars.md): Display some information as a progress bar, gauge, or similar. They are highly customizable, and can be horizontal and vertical as well.
