You can either add a layer directly into the layers object in layers.js, or declare it separately and then do "addLayer(layername, layerdata)" (good for breaking things up into smaller files)
You still need to add nodes to the tree in the HTML, add hotkeys, and do any non-standard displaying in the HTML. (You can use <divv-if="layer=='x'">Blah blah</div> to add sections to specific layers)
baseResource: The resource that determines how much of the main currency you gain on reset.
baseAmount() - How you get the current value of baseResource (e.g. baseAmount() {player.points})
requires() - A function that determines how much base resource you need to reset as a Decimal value. It can return a constant value, or change based on your order.
type: can be "normal" or "static". "normal" means the amount of currency you gain is independent of its current amount (like Prestige). "static" means that the cost grows depending on how much you already have (like Boosters). They both use different formulas. normal = x^exponent, static is base^(x^exponent)
exponent: Prestige currency exponent
base: Prestige currency base, only needed for "static" layers
resCeil: Bool, true if the resource needs to be rounded up
canBuyMax() - Only needed for static layers, used to determine if buying max is permitted.
gainMult(), gainExp() - Used to determine the multiplier and exponent on resource gain from upgrades and boosts and such. Plug all of them in here.
onPrestige(gain) - Optional, Triggers when this layer prestiges, just before you gain the currency. Can be used to have secondary resource gain on prestige, or to recalculate things or whatnot.
-----Other features-----
doReset(resettingLayer) - Optional, is triggered when a layer on a row greater than or equal to this one. If you use it, you can choose what to keep via milestones and such. Without it, the default is to reset everything on the row, but only if it was triggered by a higher layer.
convertToDecimal() - Only needed if you have non-standard Decimal values in startData, to these values from strings to Decimals after loading.
layerShown() - Returns a bool determining if this layer's node should be visible on the tree.
update(diff) - Optional, part of the main loop, use it for any passive resource production or time-based things. diff is the time since the last update.
automate() - Optional, use it to activate any autobuyers or auto-resets or similar on this layer, if appropriate.
updateTemp() - Optional, use it to update anything in the "temp" object.
resetsNothing() - Optional, returns true if this layer shouldn't trigger any resets.
incr_order: Optional, an array of layer names, their order will increase by 1 when this one is first unlocked. Can be empty.
branches: Optional, an array of pairs consisting of a layer name and a number from 1 to 3. When this layer is visible, for each pair, there will be a branch from this layer to the other layer with a color determined by the number.