Module:Chapter Infobox

For Previous Chapter:

num must be the current chapter number, this removes the need for all the #expr calls {{#invoke:Chapter Infobox|prev_chapter|num}}

For Next Chapter:

num must be the current chapter number, this removes the need for all the #expr calls {{#invoke:Chapter Infobox|next_chapter|num}}

Code uses/calls Module:Which_Chapter

---

local wc = require("Module:Which_Chapter")

local mod = {}

---@return string
function mod.prev_chapter(frame)
    local args = frame.args
    local parent = frame:getParent()
    local pargs={}
    if parent then pargs=parent.args end
    local num = args[1] or pargs[1] or ""
    local n = tonumber(num) or 0
    if n - 1 <= 0 then
        return "N/A"
    else
        frame.args[1] = n - 1
        return "[[" .. wc.where_chapter(frame) .. "]]"
    end
end

---@return string
function mod.next_chapter(frame)
    local args = frame.args
    local parent = frame:getParent()
    local pargs={}
    if parent then pargs=parent.args end
    local num = args[1] or pargs[1] or ""
    local n = tonumber(num) or #wc.chapters + 1
    frame.args[1] = n + 1
    local ret = wc.where_chapter(frame)
    if ret ~= "TBA" then return "[[" .. ret .. "]]" else return ret end
end

return mod