From d4c10fe693ceb0e71efa7ee5e9633e35ecd2e42c Mon Sep 17 00:00:00 2001
From: josef <josef.aidt@gmail.com>
Date: Tue, 27 Aug 2024 13:56:22 -0700
Subject: [PATCH] add check to `@aws-amplify/backend` to throw early in a
 browser context (#1810)

* add check to secret() to throw early in a browser context

* "client-side applications" -> "the browser"

* lift "is browser" check to a utility, execute at package entrypoint

* remove stale check from secret()

* update changeset description

* Update packages/backend/src/is_browser.ts

Co-authored-by: Kamil Sobol <sobol.k.r@gmail.com>

---------

Co-authored-by: Kamil Sobol <sobol.k.r@gmail.com>
---
 .changeset/friendly-cameras-trade.md    |  5 +++++
 packages/backend/src/index.ts           |  8 ++++++++
 packages/backend/src/is_browser.test.ts | 25 +++++++++++++++++++++++++
 packages/backend/src/is_browser.ts      |  7 +++++++
 4 files changed, 45 insertions(+)
 create mode 100644 .changeset/friendly-cameras-trade.md
 create mode 100644 packages/backend/src/is_browser.test.ts
 create mode 100644 packages/backend/src/is_browser.ts

diff --git a/.changeset/friendly-cameras-trade.md b/.changeset/friendly-cameras-trade.md
new file mode 100644
index 0000000000..0917401440
--- /dev/null
+++ b/.changeset/friendly-cameras-trade.md
@@ -0,0 +1,5 @@
+---
+'@aws-amplify/backend': patch
+---
+
+add check to `@aws-amplify/backend` entrypoint to throw early in a browser context
diff --git a/packages/backend/src/index.ts b/packages/backend/src/index.ts
index 039b5de54c..46adc6515e 100644
--- a/packages/backend/src/index.ts
+++ b/packages/backend/src/index.ts
@@ -1,3 +1,11 @@
+import { isBrowser } from './is_browser.js';
+
+if (isBrowser()) {
+  throw new Error(
+    'This package is for backend use only and should not be used in a browser environment.'
+  );
+}
+
 export { defineBackend } from './backend_factory.js';
 export * from './backend.js';
 export * from './secret.js';
diff --git a/packages/backend/src/is_browser.test.ts b/packages/backend/src/is_browser.test.ts
new file mode 100644
index 0000000000..cbe64c99bc
--- /dev/null
+++ b/packages/backend/src/is_browser.test.ts
@@ -0,0 +1,25 @@
+import { equal } from 'node:assert/strict';
+import { afterEach, describe, it } from 'node:test';
+import { isBrowser } from './is_browser.js';
+
+void describe('is browser', () => {
+  void afterEach(() => {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    delete (global as any).window;
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    delete (global as any).document;
+  });
+
+  void it('should be true in a browser context', () => {
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    (global as any).window = {};
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    (global as any).document = {};
+
+    equal(isBrowser(), true);
+  });
+
+  void it('should be false in a node context', () => {
+    equal(isBrowser(), false);
+  });
+});
diff --git a/packages/backend/src/is_browser.ts b/packages/backend/src/is_browser.ts
new file mode 100644
index 0000000000..4224ee1b4f
--- /dev/null
+++ b/packages/backend/src/is_browser.ts
@@ -0,0 +1,7 @@
+/**
+ * Checks whether we are in a browser
+ */
+export const isBrowser = () => {
+  // @ts-expect-error we're checking for browser context and globalThis does not have an index signature
+  return typeof globalThis.window !== 'undefined';
+};