Module:If preview/configuration

This Lua module is used in system messages.
Changes to it can cause immediate changes to the Wikipedia user interface.
To avoid major disruption, any changes should be tested in the module's /sandbox or /testcases subpages, or in your own module sandbox. The tested changes can be added to this page in a single edit. Please discuss changes on the talk page before implementing them.

Dis module dey do the main work for checking whether the page dey preview mode or not. Dem separate am into ein own module so mw.loadData go run am only once for each page, instead of running am every time somebody use am.

--[[
We perform the actual check for whether this is a preview here since
preprocessing is relatively expensive.
]]
local frame = mw.getCurrentFrame()

local function is_preview()
	local revision_id = frame:preprocess('{{REVISIONID}}')
	-- {{REVISIONID}} is usually the empty string when previewed.
	-- I don't know why we're checking for nil but hey, maybe someday things
	-- would have broken
	return revision_id == nil or revision_id == ''
end

local function templatestyles()
	return frame:extensionTag{
		name = 'templatestyles', args = { src = 'Module:If preview/styles.css' }
	}
end

return {
	preview = is_preview(),
	templatestyles = templatestyles(),
	warning_infrastructure = '%s<div class="preview-warning"><strong>Preview warning:</strong> %s</div>',
	missing_warning = 'The template has no warning text. Please add a warning.'
}