From d2fba7852212d50e5a5cd03616010cc7139b79ae Mon Sep 17 00:00:00 2001
From: Wout De Puysseleir <woutdp@gmail.com>
Date: Sat, 25 Mar 2023 13:50:58 -0700
Subject: [PATCH] Make it possible to disable SSR

---
 README.md        | 18 ++++++++++++++++++
 lib/component.ex |  9 +++++++--
 lib/ssr.ex       | 16 ++++++++++++++--
 3 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 70abf3b..f7484b2 100644
--- a/README.md
+++ b/README.md
@@ -103,6 +103,7 @@ Svelte components need to go into the `assets/svelte` directory
 - Set the `name` of the Svelte component.
 - _Optional:_ Provide the `props` you want to use that should be reactive as a map to the props field
 - _Optional:_ Provide `class` to set the class attribute on the root svelte element
+- _Optional:_ Set `ssr` to false to disable server-side rendering
 
 e.g. If your component is named `assets/svelte/Example.svelte`:
 
@@ -222,6 +223,23 @@ e.g. Typescript
 cd assets && npm install --save-dev typescript
 ```
 
+### SSR
+
+SSR is enabled by default, but if you don't want to use Server-Side Rendering for Svelte, you can do 2 things:
+
+#### Globally
+
+If you don't want to use SSR on any component you can disable it globally.
+This will automatically be the case if you don't include the `NodeJs` supervisor in you `application.ex` file
+
+#### Component
+
+To disable SSR on a specific component, set the `ssr` property to false. Like so:
+
+```
+<LiveSvelte.render name="Example" ssr={false} />
+```
+
 ## Caveats
 
 ### Slot Interoperability
diff --git a/lib/component.ex b/lib/component.ex
index 0b4a9ba..3eace3c 100644
--- a/lib/component.ex
+++ b/lib/component.ex
@@ -8,6 +8,7 @@ defmodule LiveSvelte do
   attr(:props, :map, default: %{})
   attr(:name, :string, required: true)
   attr(:class, :string, default: nil)
+  attr(:ssr, :boolean, default: true)
 
   slot(:inner_block)
 
@@ -23,8 +24,12 @@ defmodule LiveSvelte do
       |> Slots.js_process()
 
     ssr_code =
-      if init do
-        SSR.render(assigns.name, Map.get(assigns, :props, %{}), slots)
+      if init and Map.get(assigns, :ssr) do
+        try do
+          SSR.render(assigns.name, Map.get(assigns, :props, %{}), slots)
+        rescue
+          SSR.NodeNotConfigured -> nil
+        end
       end
 
     assigns =
diff --git a/lib/ssr.ex b/lib/ssr.ex
index 905d00e..2b51be5 100644
--- a/lib/ssr.ex
+++ b/lib/ssr.ex
@@ -1,7 +1,19 @@
+defmodule LiveSvelte.SSR.NodeNotConfigured do
+  defexception message: """
+                 NodeJS is not configured. Please add the following to your application.ex:
+                 {NodeJS.Supervisor, [path: "#{File.cwd!()}/assets", pool_size: 4]},
+               """
+end
+
 defmodule LiveSvelte.SSR do
   def render(name, props, slots \\ nil)
   def render(name, nil, slots), do: render(name, %{}, slots)
 
-  def render(name, props, slots),
-    do: NodeJS.call!({"js/render", "render"}, [name, props, slots])
+  def render(name, props, slots) do
+    try do
+      NodeJS.call!({"js/render", "render"}, [name, props, slots])
+    catch
+      :exit, {:noproc, _} -> raise LiveSvelte.SSR.NodeNotConfigured
+    end
+  end
 end