From 26038c82438ed3d905dcbf92ce9a4e96209c0967 Mon Sep 17 00:00:00 2001
From: Adeel Raza <adeelr@gmail.com>
Date: Wed, 5 Aug 2026 08:49:47 +0400
Subject: [PATCH] feat(demo): add image upload so users can try their own
 images
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Content-Type: text/plain; charset=UTF-8
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Adds an "Upload image…" action to the demo sidebar backed by a hidden
file input. The file is read client-side via FileReader.readAsDataURL
and flows through the existing image prop / serialized reset chain —
no server involved.

Hardening from adversarial review:
- MIME + 20 MB size gate (accept="image/*" is only a picker hint)
- read token + abort so a slow read can't overwrite a newer pick
- reader.error logged; input value cleared before the callback so
  re-selecting the same file always fires onChange

Co-Authored-By: Claude <noreply@anthropic.com>
---
 demo/src/App.tsx     | 37 +++++++++++++++++++++++++++++++++++++
 demo/src/Sidebar.tsx | 21 ++++++++++++++++++++-
 2 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/demo/src/App.tsx b/demo/src/App.tsx
index e658424..527f79c 100644
--- a/demo/src/App.tsx
+++ b/demo/src/App.tsx
@@ -14,6 +14,8 @@ const SAMPLE_IMAGES = [
   'https://picsum.photos/id/1040/1200/800',
 ];
 
+const MAX_UPLOAD_BYTES = 20 * 1024 * 1024;
+
 const allToolsEnabled = () =>
   Object.fromEntries(TOOL_NAMES.map((tool) => [tool, true])) as Record<
     ToolName,
@@ -32,12 +34,46 @@ export default function App() {
   const [saved, setSaved] = useState<ImageEditorSaveResult | null>(null);
   const [status, setStatus] = useState('Loading editor…');
 
+  // Invalidates in-flight file reads so a slow read can never overwrite a
+  // newer image choice (upload or sample) after the fact.
+  const readTokenRef = useRef(0);
+  const readerRef = useRef<FileReader | null>(null);
+
   const nextImage = () => {
+    readTokenRef.current++;
+    readerRef.current?.abort();
     const index = SAMPLE_IMAGES.indexOf(image);
     setImage(SAMPLE_IMAGES[(index + 1) % SAMPLE_IMAGES.length]);
     setStatus('Image changed (reset)');
   };
 
+  const uploadImage = (file: File) => {
+    // accept="image/*" is only a picker hint — enforce type and size here.
+    if (!file.type.startsWith('image/')) {
+      setStatus(`"${file.name}" is not an image`);
+      return;
+    }
+    if (file.size > MAX_UPLOAD_BYTES) {
+      setStatus(`"${file.name}" is too large (max 20 MB)`);
+      return;
+    }
+    readerRef.current?.abort();
+    const token = ++readTokenRef.current;
+    const reader = new FileReader();
+    readerRef.current = reader;
+    reader.onload = () => {
+      if (token !== readTokenRef.current) return;
+      setImage(reader.result as string);
+      setStatus(`Loaded "${file.name}" (reset)`);
+    };
+    reader.onerror = () => {
+      if (token !== readTokenRef.current) return;
+      console.error('[demo] file read failed', reader.error);
+      setStatus(`Could not read "${file.name}"`);
+    };
+    reader.readAsDataURL(file);
+  };
+
   const checkChanges = () => {
     const editor = editorRef.current?.editor;
     if (!editor) return;
@@ -82,6 +118,7 @@ export default function App() {
             tools={tools}
             onToolToggle={toggleTool}
             onChangeImage={nextImage}
+            onUploadImage={uploadImage}
             onCheckChanges={checkChanges}
             onSnapshot={snapshot}
           />
diff --git a/demo/src/Sidebar.tsx b/demo/src/Sidebar.tsx
index 8e9624e..6babf7e 100644
--- a/demo/src/Sidebar.tsx
+++ b/demo/src/Sidebar.tsx
@@ -1,4 +1,4 @@
-import React from 'react';
+import React, { useRef } from 'react';
 
 import type { UnlayerLocale } from '@unlayer/types';
 
@@ -31,16 +31,35 @@ interface SidebarProps {
   tools: Record<ToolName, boolean>;
   onToolToggle(tool: ToolName): void;
   onChangeImage(): void;
+  onUploadImage(file: File): void;
   onCheckChanges(): void;
   onSnapshot(): void;
 }
 
 export default function Sidebar(props: SidebarProps) {
+  const fileInputRef = useRef<HTMLInputElement>(null);
+
   return (
     <aside className="sidebar">
       <section className="section">
         <h2 className="section-label">Actions</h2>
         <button onClick={props.onChangeImage}>Change image</button>
+        <button onClick={() => fileInputRef.current?.click()}>
+          Upload image…
+        </button>
+        <input
+          ref={fileInputRef}
+          type="file"
+          accept="image/*"
+          hidden
+          onChange={(event) => {
+            const file = event.target.files?.[0];
+            // Clear before the callback so re-selecting the same file always
+            // fires onChange, even if the handler throws.
+            event.target.value = '';
+            if (file) props.onUploadImage(file);
+          }}
+        />
         <button onClick={props.onCheckChanges}>Has changes?</button>
         <button onClick={props.onSnapshot}>Snapshot</button>
       </section>