Merge pull request #120 from Elttob/pr-820hydrate

Implement instance hydration

src/Instances/Hydrate.lua

@@ -0,0 +1,20 @@
+--!strict
+
+--[[
+	Processes and returns an existing instance, with options for setting
+	properties, event handlers and other attributes on the instance.
+]]
+
+local Package = script.Parent.Parent
+local PubTypes = require(Package.PubTypes)
+local semiWeakRef = require(Package.Instances.semiWeakRef)
+local applyInstanceProps = require(Package.Instances.applyInstanceProps)
+
+local function Hydrate(target: Instance)
+	return function(props: PubTypes.PropertyTable): Instance
+		applyInstanceProps(props, semiWeakRef(target))
+		return target
+	end
+end
+
+return Hydrate

src/Logging/messages.lua

@@ -11,6 +11,7 @@ return {
 	cannotConnectEvent = "The %s class doesn't have an event called '%s'.",
 	cannotCreateClass = "Can't create a new instance of class '%s'.",
 	computedCallbackError = "Computed callback error: ERROR_MESSAGE",
+	duplicatePropertyKey = "",
 	invalidChangeHandler = "The change handler for the '%s' property must be a function.",
 	invalidEventHandler = "The handler for the '%s' event must be a function.",
 	invalidPropertyType = "'%s.%s' expected a '%s' type, but got a '%s' type.",
@@ -26,7 +27,7 @@ return {
 	springTypeMismatch = "The type '%s' doesn't match the spring's type '%s'.",
 	strictReadError = "'%s' is not a valid member of '%s'.",
 	unknownMessage = "Unknown error: ERROR_MESSAGE",
-	unrecognisedChildType = "'%s' type children aren't accepted as children in `New`.",
-	unrecognisedPropertyKey = "'%s' keys aren't accepted in the property table of `New`.",
-	unrecognisedPropertyStage = "The special key stage '%s' isn't recognised by `New`."
+	unrecognisedChildType = "'%s' type children aren't accepted by `[Children]`.",
+	unrecognisedPropertyKey = "'%s' keys aren't accepted in property tables.",
+	unrecognisedPropertyStage = "'%s' isn't a valid stage for a special key to be applied at."
 }

src/init.lua

@@ -21,6 +21,7 @@ type Fusion = {
 	version: PubTypes.Version,
 
 	New: (className: string) -> ((propertyTable: PubTypes.PropertyTable) -> Instance),
+	Hydrate: (target: Instance) -> ((propertyTable: PubTypes.PropertyTable) -> Instance),
 	Ref: PubTypes.SpecialKey,
 	Children: PubTypes.SpecialKey,
 	OnEvent: (eventName: string) -> PubTypes.SpecialKey,
@@ -39,6 +40,7 @@ return restrictRead("Fusion", {
 	version = {major = 0, minor = 2, isRelease = false},
 
 	New = require(script.Instances.New),
+	Hydrate = require(script.Instances.Hydrate),
 	Ref = require(script.Instances.Ref),
 	Children = require(script.Instances.Children),
 	OnEvent = require(script.Instances.OnEvent),

test/Instances/Hydrate.spec.lua

@@ -0,0 +1,33 @@
+local Package = game:GetService("ReplicatedStorage").Fusion
+local Hydrate = require(Package.Instances.Hydrate)
+
+return function()
+	it("should return the instance it was passed", function()
+		local ins = Instance.new("Folder")
+
+		expect(Hydrate(ins) {}).to.equal(ins)
+	end)
+
+	it("should apply properties to the instance", function()
+		local ins = Instance.new("Folder")
+
+		Hydrate(ins) {
+			Name = "Jeremy"
+		}
+
+		expect(ins.Name).to.equal("Jeremy")
+	end)
+
+	it("should not inhibit garbage collection", function()
+		local ref = setmetatable({}, {__mode = "v"})
+		do
+			ref[1] = Hydrate(Instance.new("Folder")) {}
+		end
+
+		local startTime = os.clock()
+		repeat
+			task.wait()
+		until ref[1] == nil or os.clock() > startTime + 5
+		expect(ref[1]).to.equal(nil)
+	end)
+end

test/init.spec.lua

@@ -9,6 +9,7 @@ return function()
 			version = "table",
 
 			New = "function",
+			Hydrate = "function",
 			Ref = "table",
 			Children = "table",
 			OnEvent = "function",