From 80883cfb8f38dce53cef27a573ef48a7da432853 Mon Sep 17 00:00:00 2001
From: Daniel Roe <daniel@roe.dev>
Date: Mon, 18 Oct 2021 17:08:37 +0100
Subject: [PATCH] fix(nitro): improve externals error handling (#1188)

---
 packages/nitro/src/rollup/plugins/externals.ts | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/packages/nitro/src/rollup/plugins/externals.ts b/packages/nitro/src/rollup/plugins/externals.ts
index 12e3a865ac..85e1de65e4 100644
--- a/packages/nitro/src/rollup/plugins/externals.ts
+++ b/packages/nitro/src/rollup/plugins/externals.ts
@@ -52,8 +52,12 @@ export function externals (opts: NodeExternalsOptions): Plugin {
 
       // Track externals
       if (opts.trace !== false) {
-        const resolved = await this.resolve(originalId, importer, { ...options, skipSelf: true }).then(r => r.id)
-        trackedExternals.add(resolved)
+        const resolved = await this.resolve(originalId, importer, { ...options, skipSelf: true })
+        if (!resolved) {
+          console.warn(`Could not resolve \`${originalId}\`. Have you installed it?`)
+        } else {
+          trackedExternals.add(resolved.id)
+        }
       }
 
       return {