更新 README 文档，添加 JSON 预览功能的示例图片；新增 JsonTreeNode 组件以支持树形结构展示 JSON 数据

README.md

@@ -105,3 +105,10 @@ npm run preview
 - 日期字段会尽量兼容 Excel 序列日期（数字日期）
 - 当 `excludeIfEmpty = true` 时，空值字段不会出现在输出 JSON 中
 - 若目标字段包含 `.`，会按路径写入嵌套对象
+
+## <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͼ
+
+![<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͼ 1](doc/images/image1.png)
+
+![<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ͼ 2](doc/images/image2.png)
+

src/lib/components/JsonPreview.svelte

@@ -1,4 +1,6 @@
 <script lang="ts">
+	import JsonTreeNode from './JsonTreeNode.svelte';
+
 	let { json, onupdate }: {
 		json: Record<string, unknown>[];
 		onupdate?: (edited: string) => void;
@@ -6,20 +8,21 @@
 
 	const MAX_PREVIEW_CHARS = 2000;
 	const MAX_PREVIEW_LINES = 50;
+	const MAX_TREE_ITEMS = 50;
 
-	let editing = $state(false);
+	type ViewMode = 'tree' | 'raw' | 'edit';
+	let viewMode = $state<ViewMode>('tree');
 	let editText = $state('');
 	let parseError = $state('');
 
 	const jsonString = $derived(JSON.stringify(json, null, 2));
 
-	// Truncation for preview
+	// Truncation for raw preview
 	const truncated = $derived.by(() => {
 		const lines = jsonString.split('\n');
 		if (jsonString.length <= MAX_PREVIEW_CHARS && lines.length <= MAX_PREVIEW_LINES) {
 			return { text: jsonString, isTruncated: false, totalChars: jsonString.length, totalLines: lines.length };
 		}
-		// Truncate by line first, then by char
 		let preview = lines.slice(0, MAX_PREVIEW_LINES).join('\n');
 		if (preview.length > MAX_PREVIEW_CHARS) {
 			preview = preview.slice(0, MAX_PREVIEW_CHARS);
@@ -27,9 +30,13 @@
 		return { text: preview, isTruncated: true, totalChars: jsonString.length, totalLines: lines.length };
 	});
 
+	// Tree view shows limited items for performance
+	const treeData = $derived(json.length > MAX_TREE_ITEMS ? json.slice(0, MAX_TREE_ITEMS) : json);
+	const treeTruncated = $derived(json.length > MAX_TREE_ITEMS);
+
 	// Sync from upstream when not editing
 	$effect(() => {
-		if (!editing) {
+		if (viewMode !== 'edit') {
 			editText = jsonString;
 		}
 	});
@@ -48,12 +55,12 @@
 
 	function startEdit() {
 		editText = jsonString;
-		editing = true;
+		viewMode = 'edit';
 		parseError = '';
 	}
 
 	function cancelEdit() {
-		editing = false;
+		viewMode = 'tree';
 		parseError = '';
 		editText = jsonString;
 	}
@@ -62,7 +69,7 @@
 		try {
 			JSON.parse(editText);
 			parseError = '';
-			editing = false;
+			viewMode = 'tree';
 			onupdate?.(editText);
 		} catch {
 			parseError = 'JSON 格式错误，请检查语法';
@@ -71,13 +78,14 @@
 </script>
 
 <div class="flex h-full flex-col overflow-hidden">
+	<!-- Header -->
 	<div class="flex flex-shrink-0 items-center justify-between border-b border-gray-200 bg-gray-50 px-4 py-2">
 		<h3 class="text-sm font-semibold text-gray-700">
-			JSON 预览
+			JSON
-			<span class="ml-2 text-xs font-normal text-gray-400">{json.length} 条记录</span>
+			<span class="ml-1 text-xs font-normal text-gray-400">{json.length} 条</span>
 		</h3>
-		<div class="flex items-center gap-1.5">
+		<div class="flex items-center gap-1">
-			{#if editing}
+			{#if viewMode === 'edit'}
 				<button onclick={applyEdit} class="rounded bg-blue-600 px-2 py-1 text-xs text-white hover:bg-blue-700 cursor-pointer">
 					应用
 				</button>
@@ -85,7 +93,24 @@
 					取消
 				</button>
 			{:else}
-				<button onclick={startEdit} class="rounded border border-gray-300 px-2 py-1 text-xs text-gray-500 hover:bg-gray-200 cursor-pointer">
+				<!-- View mode tabs -->
+				<div class="flex rounded border border-gray-300 text-xs">
+					<button
+						onclick={() => (viewMode = 'tree')}
+						class="px-2 py-1 cursor-pointer {viewMode === 'tree' ? 'bg-gray-200 text-gray-800 font-medium' : 'bg-white text-gray-500 hover:bg-gray-50'}"
+						style="border-radius: 3px 0 0 3px"
+					>
+						树形
+					</button>
+					<button
+						onclick={() => (viewMode = 'raw')}
+						class="border-l border-gray-300 px-2 py-1 cursor-pointer {viewMode === 'raw' ? 'bg-gray-200 text-gray-800 font-medium' : 'bg-white text-gray-500 hover:bg-gray-50'}"
+						style="border-radius: 0 3px 3px 0"
+					>
+						源码
+					</button>
+				</div>
+				<button onclick={startEdit} class="ml-1 rounded border border-gray-300 px-2 py-1 text-xs text-gray-500 hover:bg-gray-200 cursor-pointer">
 					编辑
 				</button>
 			{/if}
@@ -96,21 +121,30 @@
 		<div class="flex-shrink-0 bg-red-50 px-4 py-1.5 text-xs text-red-600">{parseError}</div>
 	{/if}
 
+	<!-- Content -->
 	<div class="json-preview flex-1 overflow-hidden">
-		{#if editing}
+		{#if viewMode === 'edit'}
-			<!-- Plain textarea for editing — no overlay highlighting to avoid lag -->
 			<textarea
 				bind:value={editText}
 				oninput={() => { parseError = ''; }}
 				spellcheck="false"
 				class="json-textarea h-full w-full resize-none overflow-auto border-0 bg-transparent font-mono text-xs leading-relaxed text-gray-700 outline-none"
 			></textarea>
+		{:else if viewMode === 'tree'}
+			<div class="h-full overflow-auto px-4 py-3">
+				<JsonTreeNode value={treeData} defaultOpen={true} />
+				{#if treeTruncated}
+					<div class="mt-2 border-t border-amber-200 bg-amber-50 px-3 py-2 text-xs text-amber-700">
+						&#x26A0;&#xFE0F; 树形视图仅展示前 {MAX_TREE_ITEMS} 条记录（共 {json.length.toLocaleString()} 条）。请下载或复制查看完整数据。
+					</div>
+				{/if}
+			</div>
 		{:else}
 			<div class="h-full overflow-auto">
 				<pre class="json-content whitespace-pre font-mono text-xs leading-relaxed text-gray-500">{@html highlight(truncated.text)}</pre>
 				{#if truncated.isTruncated}
-					<div class="truncation-notice sticky bottom-0 border-t border-amber-200 bg-amber-50 px-4 py-2 text-xs text-amber-700">
+					<div class="sticky bottom-0 border-t border-amber-200 bg-amber-50 px-4 py-2 text-xs text-amber-700">
-						&#x26A0;&#xFE0F; 预览已截断以提升性能（显示 {Math.min(MAX_PREVIEW_CHARS, truncated.text.length).toLocaleString()}/{truncated.totalChars.toLocaleString()} 字符，{Math.min(MAX_PREVIEW_LINES, truncated.totalLines)}/{truncated.totalLines.toLocaleString()} 行）。请点击下载或复制查看完整数据。
+						&#x26A0;&#xFE0F; 预览已截断（显示 {Math.min(MAX_PREVIEW_CHARS, truncated.text.length).toLocaleString()}/{truncated.totalChars.toLocaleString()} 字符，{Math.min(MAX_PREVIEW_LINES, truncated.totalLines)}/{truncated.totalLines.toLocaleString()} 行）。请下载或复制查看完整数据。
 					</div>
 				{/if}
 			</div>

src/lib/components/JsonTreeNode.svelte

@@ -0,0 +1,98 @@
+<script lang="ts">
+	import JsonTreeNode from './JsonTreeNode.svelte';
+
+	let {
+		value,
+		keyName = undefined,
+		depth = 0,
+		defaultOpen = false
+	}: {
+		value: unknown;
+		keyName?: string | number;
+		depth?: number;
+		defaultOpen?: boolean;
+	} = $props();
+
+	let open = $state(defaultOpen);
+
+	const valueType = $derived(
+		value === null ? 'null'
+		: Array.isArray(value) ? 'array'
+		: typeof value === 'object' ? 'object'
+		: typeof value
+	);
+
+	const isExpandable = $derived(valueType === 'object' || valueType === 'array');
+	const entries = $derived(
+		isExpandable
+			? Object.entries(value as Record<string, unknown>)
+			: []
+	);
+	const childCount = $derived(entries.length);
+
+	const preview = $derived(
+		valueType === 'array' ? `Array(${childCount})`
+		: valueType === 'object' ? `{${childCount}}`
+		: ''
+	);
+</script>
+
+<div class="tree-node" style="padding-left: {depth > 0 ? 16 : 0}px">
+	<div class="node-row flex items-baseline gap-1 py-0.5">
+		{#if isExpandable}
+			<button
+				onclick={() => (open = !open)}
+				class="toggle flex-shrink-0 cursor-pointer border-0 bg-transparent p-0 font-mono text-[10px] leading-none text-gray-400 hover:text-gray-700"
+				aria-label={open ? '折叠' : '展开'}
+			>
+				{open ? '▼' : '▶'}
+			</button>
+		{:else}
+			<span class="w-[10px] flex-shrink-0"></span>
+		{/if}
+
+		{#if keyName !== undefined}
+			<span class="node-key font-mono text-xs font-medium text-gray-800">
+				{typeof keyName === 'number' ? keyName : `"${keyName}"`}</span><span class="text-xs text-gray-400">:&nbsp;</span>
+		{/if}
+
+		{#if isExpandable}
+			<button
+				onclick={() => (open = !open)}
+				class="cursor-pointer border-0 bg-transparent p-0 font-mono text-xs text-gray-400 hover:text-gray-600"
+			>
+				{#if open}
+					{valueType === 'array' ? '[' : '{'}
+				{:else}
+					<span class="text-gray-400">{preview}</span>
+				{/if}
+			</button>
+		{:else if valueType === 'string'}
+			<span class="font-mono text-xs text-green-700">"{String(value)}"</span>
+		{:else if valueType === 'number'}
+			<span class="font-mono text-xs text-blue-700">{String(value)}</span>
+		{:else if valueType === 'boolean'}
+			<span class="font-mono text-xs text-red-600">{String(value)}</span>
+		{:else if valueType === 'null'}
+			<span class="font-mono text-xs italic text-gray-400">null</span>
+		{:else}
+			<span class="font-mono text-xs text-gray-600">{String(value)}</span>
+		{/if}
+	</div>
+
+	{#if isExpandable && open}
+		<div class="tree-children border-l border-gray-200">
+			{#each entries as [childKey, childVal], i (childKey)}
+				<JsonTreeNode
+					value={childVal}
+					keyName={valueType === 'array' ? i : childKey}
+					depth={depth + 1}
+					defaultOpen={depth < 1}
+				/>
+			{/each}
+		</div>
+		<div style="padding-left: {depth > 0 ? 16 : 0}px">
+			<span class="font-mono text-xs text-gray-400">{valueType === 'array' ? ']' : '}'}</span>
+		</div>
+	{/if}
+</div>