From a25d6c82b5aec2bd2049f24f6822bca8622d7a43 Mon Sep 17 00:00:00 2001
From: Folkert <folkert@folkertdev.nl>
Date: Mon, 20 Sep 2021 23:11:24 +0200
Subject: [PATCH] provide roc_panic from javascript

---
 examples/hello-web/platform/host.js  | 7 ++-----
 examples/hello-web/platform/host.zig | 8 +-------
 2 files changed, 3 insertions(+), 12 deletions(-)

diff --git a/examples/hello-web/platform/host.js b/examples/hello-web/platform/host.js
index 9e3548aa26..0d953eabff 100644
--- a/examples/hello-web/platform/host.js
+++ b/examples/hello-web/platform/host.js
@@ -11,12 +11,9 @@ async function roc_web_platform_run(wasm_filename, callback) {
 
   const importObj = {
     wasi_snapshot_preview1: {
-      proc_exit: (code) => {
-        if (code !== 0) {
-          console.error(`Exited with code ${code}`);
+        roc_panic: (_pointer, _tag_id) => {
+            throw 'Roc panicked!';
         }
-        exit_code = code;
-      },
     },
     env: {
       js_display_roc_string,
diff --git a/examples/hello-web/platform/host.zig b/examples/hello-web/platform/host.zig
index 961619340e..5d588d6912 100644
--- a/examples/hello-web/platform/host.zig
+++ b/examples/hello-web/platform/host.zig
@@ -43,13 +43,7 @@ export fn roc_dealloc(c_ptr: *c_void, alignment: u32) callconv(.C) void {
     free(@alignCast(@alignOf(Align), @ptrCast([*]u8, c_ptr)));
 }
 
-export fn roc_panic(c_ptr: *c_void, tag_id: u32) callconv(.C) void {
-    _ = tag_id;
-    const stderr = std.io.getStdErr().writer();
-    const msg = @ptrCast([*:0]const u8, c_ptr);
-    stderr.print("Application crashed with message\n\n    {s}\n\nShutting down\n", .{msg}) catch unreachable;
-    std.process.exit(0);
-}
+// NOTE roc_panic is provided in the JS file, so it can throw an exception
 
 const mem = std.mem;
 const Allocator = mem.Allocator;