src/create.luau

@@ -0,0 +1,75 @@
+if not game then
+    script = (require :: any) "test/wrap-require"
+    Instance = require("test/mock").Instance
+    typeof = require("test/mock").typeof
+end
+
+local throw = require(script.Parent.throw)
+local defaults = require(script.Parent.defaults)
+local apply = require(script.Parent.apply)
+local memoize = require(script.Parent.memoize)
+
+local function createInstance(className: string)
+    local success, instance: Instance = pcall(Instance.new, className :: any)
+    if success == false then throw(`invalid class name, could not create instance of class { className }`) end
+
+    local default: { [string]: unknown }? = defaults[className]
+    if default then
+        for i, v in next, default do
+            (instance :: any)[i] = v
+        end
+    end
+
+    return function(properties: { [any]: unknown }): Instance
+        return apply(instance:Clone(), properties)    
+    end  
+end; createInstance = memoize(createInstance)
+
+local function cloneInstance(instance: Instance)
+    return function(properties: { [any]: unknown }): Instance
+        local clone = instance:Clone()
+        if not clone then error("Attempt to clone a non-archivable instance", 3) end
+        return apply(clone, properties)
+    end
+end
+
+local function create(classNameOrInstance: string|Instance)
+    if type(classNameOrInstance) == "string" then
+        return createInstance(classNameOrInstance)
+    elseif typeof(classNameOrInstance) == "Instance" then
+        return cloneInstance(classNameOrInstance)
+    else
+        error("Bad argument #1, expected string or instance, got "..typeof(classNameOrInstance), 2)
+    end
+end
+
+type Props = { [any]: any }
+return (create :: any) :: 
+( <T>(T & Instance) -> (Props) -> T ) &
+( ("Folder") -> (Props) -> Folder ) &
+( ("BillboardGui") -> (Props) -> BillboardGui ) &
+( ("CanvasGroup") -> (Props) -> CanvasGroup ) &
+( ("Frame") -> (Props) -> Frame ) &
+( ("ImageButton") -> (Props) -> ImageButton ) &
+( ("ImageLabel") -> (Props) -> ImageLabel ) &
+( ("ScreenGui") -> (Props) -> ScreenGui ) &
+( ("ScrollingFrame") -> (Props) -> ScrollingFrame ) &
+( ("SurfaceGui") -> (Props) -> SurfaceGui ) &
+( ("TextBox") -> (Props) -> TextBox ) &
+( ("TextButton") -> (Props) -> TextButton ) &
+( ("TextLabel") -> (Props) -> TextLabel ) &
+( ("UIAspectRatioConstraint") -> (Props) -> UIAspectRatioConstraint ) &
+( ("UICorner") -> (Props) -> UICorner ) &
+( ("UIGradient") -> (Props) -> UIGradient ) &
+( ("UIGridLayout") -> (Props) -> UIGridLayout ) &
+( ("UIListLayout") -> (Props) -> UIListLayout ) &
+( ("UIPadding") -> (Props) -> UIPadding ) &
+( ("UIPageLayout") -> (Props) -> UIPageLayout ) &
+( ("UIScale") -> (Props) -> UIScale ) &
+( ("UISizeConstraint") -> (Props) -> UISizeConstraint ) &
+( ("UIStroke") -> (Props) -> UIStroke ) &
+( ("UITableLayout") -> (Props) -> UITableLayout ) &
+( ("UITextSizeConstraint") -> (Props) -> UITextSizeConstraint ) &
+( ("VideoFrame") -> (Props) -> VideoFrame ) &
+( ("ViewportFrame") -> (Props) -> ViewportFrame ) &
+( (string) -> (Props) -> Instance )