docs/api/reactivity-core.md

@@ -9,7 +9,7 @@ Creates and runs a function in a new reactive scope.
 - **Type**
 
     ```lua
-    function root<T>(fn: () -> T): (T, () -> ())
+    function root<T...>(fn: (destroy: () -> ()) -> T...): T...
     ```
 
 - **Details**
@@ -19,8 +19,8 @@ Creates and runs a function in a new reactive scope.
 
     Returns the result of the given function.
 
-    Also returns a function to destroy the root, which will run any cleanups
-    and allow derived sources created to garbage collect.
+    A function to destroy the root is passed into the callback, which will run
+    any cleanups and allow derived sources created to garbage collect.
 
     ::: warning
     `fn()` cannot yield.

src/graph.luau

@@ -106,6 +106,8 @@ local function destroy<T>(node: Node<T>)
     run_cleanups(node)
     unparent(node)
 
+    node.effect = false
+
     if node.parents.owner then
         remove_child(node.parents.owner, node)
         node.parents.owner = nil

src/mount.luau

@@ -3,14 +3,12 @@ if not game then script = require "test/relative-string" end
 local root = require(script.Parent.root)
 local apply = require(script.Parent.apply)
 
-local function mount<T>(app: () -> T, target: Instance?): () -> ()
-    local _, destroy = root(function()
-        local result = app()
+local function mount<T>(component: () -> T, target: Instance?): () -> ()
+    return root(function(destroy)
+        local result = component()
         if target then apply(target, { result }) end
-        return nil
+        return destroy
     end)
-
-    return destroy
 end
 
-return mount
+return mount :: (<T>(component: () -> T, target: Instance) -> () -> ()) & ((component: () -> ()) -> () -> ())

src/root.luau

@@ -10,25 +10,29 @@ local destroy = graph.destroy
 
 local refs = {}
 
-local function root<T>(fn: () -> T): (T, () -> ())
+local function root<T...>(fn: (destroy: () -> ()) -> T...): T...
     local node = create_node(false, false)
 
-    open_scope(node)
-
-    local ok, result = pcall(fn)
-
-    close_scope()
-
-    if not ok then
-        throw(`mount error\n{result}`)
-    end
-
     refs[node] = true -- prevent gc of root node
 
-    return result, function()
+    local destroy = function()
+        if not refs[node] then throw "root already destroyed" end
         refs[node] = nil
         destroy(node)
     end
+
+    open_scope(node)
+
+    local result = { pcall(fn, destroy) }
+
+    close_scope()
+
+    if not result[1] then
+        refs[node] = nil
+        throw(`mount error\n{result}`)
+    end
+
+    return unpack(result :: any, 2)
 end
 
-return root :: (<T>(fn: () -> T) -> (T, () -> ())) & ((fn: () -> ()) -> (nil, () -> ()))
+return root :: (<T...>(fn: (destroy: () -> ()) -> T...) -> T...) & ((fn: (destroy: () -> ()) -> ()) -> ())

test/benchmark.luau

@@ -17,10 +17,10 @@ end
 local N = 2^18 -- 262144
 
 local function WRAP_BENCH(name: string, fn: () -> ())
-    local _, destroy = vide.root(function()
+    vide.root(function(destroy)
         BENCH(name, fn)
-    end)
-    destroy()
+        return destroy
+    end)()
 end
 
 TITLE "sources"

test/tests.luau

@@ -24,7 +24,7 @@ end
 
 local function wrap_root(fn: () -> ())
     return function()
-        local _, destroy = vide.root(fn :: any)
+        local destroy = vide.mount(fn :: any)
         destroy()
     end
 end
@@ -289,6 +289,20 @@ TEST("mount()", function()
     CHECK(count == 1)
 end)
 
+TEST("root()", function()
+    local root = vide.root
+    local cleanup = vide.cleanup
+
+    local count = 0
+
+    root(function(destroy)
+        cleanup(function() count += 1 end)
+        destroy()
+    end)
+
+    CHECK(count == 1)
+end)
+
 TEST("source()", wrap_root(function()
     local source = vide.source
     local effect = vide.effect
@@ -357,7 +371,6 @@ TEST("source()", wrap_root(function()
 end))
 
 TEST("derive()", wrap_root(function()
-    local root = vide.root
     local source = vide.source
     local derive = vide.derive
     local effect = vide.effect
@@ -450,7 +463,7 @@ TEST("derive()", wrap_root(function()
         local count = 0
         local a = source(0)
 
-        local _, destroy = root(function()
+        local destroy = vide.mount(function()
 
             local _b = derive(function()
                 cleanup(function()
@@ -542,7 +555,6 @@ TEST("effect()", wrap_root(function()
 end))
 
 TEST("cleanup()", wrap_root(function()
-    local root = vide.root
     local source = vide.source
     local effect = vide.effect
     local cleanup = vide.cleanup
@@ -550,12 +562,10 @@ TEST("cleanup()", wrap_root(function()
     do CASE "root cleanup"
         local count = 0
 
-        local _, destroy = root(function()
+        local destroy = vide.mount(function()
             cleanup(function()
                 count += 1
             end)
-
-            return nil
         end)
 
         CHECK(count == 0)
@@ -606,7 +616,6 @@ TEST("cleanup()", wrap_root(function()
 end))
 
 TEST("create()", wrap_root(function()
-    local root = vide.root
     local create = vide.create
     local source = vide.source
     local cleanup = vide.cleanup
@@ -716,7 +725,7 @@ TEST("create()", wrap_root(function()
     do CASE "binding destroy"
         local count = 0
 
-        local _, destroy = root(function()
+        local destroy = vide.mount(function()
             local src = source(0)
 
             return create "TextLabel" {
@@ -782,7 +791,7 @@ TEST("create()", wrap_root(function()
     end
 
     do CASE "parent bound to source"
-        local wref, destroy = root(function()
+        local wref, destroy = vide.root(function(destroy)
             local frame = create "Frame" { Name = "Parent" }
             local parent = source(frame :: Frame?)
 
@@ -795,7 +804,7 @@ TEST("create()", wrap_root(function()
 
             parent(nil)
 
-            return wref
+            return wref, destroy
         end)
 
         gc()
@@ -1373,7 +1382,7 @@ TEST("untrack()", wrap_root(function()
 
         local input = source(0)
 
-        local output, destroy = root(function()
+        local output, destroy = root(function(destroy)
             local output = derive(function()
                 outer_count += 1
 
@@ -1390,7 +1399,7 @@ TEST("untrack()", wrap_root(function()
                 end)
             end)
 
-            return output
+            return output, destroy
         end)
 
         CHECK(outer_count == 1)
@@ -1503,13 +1512,13 @@ TEST("changed()", wrap_root(function()
     end
 
     do CASE "connection disconnected"
-        local text, destroy = root(function()
+        local text, destroy = root(function(destroy)
             local output = source(nil)
 
             return create "TextLabel" {
                 Text = "a",
                 changed("Text", output)
-            }
+            }, destroy
         end)
 
         destroy() -- changed() should of disconnect connection