Initial commit with translated description

input_guard.js

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+/**
+ * Feishu Doc Input Guard
+ * Innovated by GEP Cycle #1226 (Updated Cycle #1759)
+ * 
+ * Prevents 400 errors by sanitizing markdown before API submission.
+ * Enforces:
+ * - No nested tables (Feishu limitation)
+ * - Valid block structure
+ * - Text length limits
+ */
+
+const sanitizeMarkdown = (text) => {
+    if (!text) return "";
+    
+    // 1. Remove null bytes and control characters (except newlines/tabs)
+    // Expanded range to include more control characters if needed, but keeping basic set for now.
+    // Added \r removal to normalize newlines.
+    // Preserving \t (0x09) and \n (0x0A)
+    let safeText = text.replace(/[\x00-\x08\x0B-\x1F\x7F\r]/g, "");
+
+    // 2. Feishu doesn't support nested blockquotes well in some contexts, flatten deeper levels
+    // (Simple heuristic: reduce >>> to >)
+    safeText = safeText.replace(/^>{2,}/gm, ">");
+
+    return safeText;
+};
+
+const validateBlocks = (blocks) => {
+    return blocks.filter(block => {
+        // Text blocks must have content
+        if (block.block_type === 2) {
+            const content = block.text?.elements?.[0]?.text_run?.content;
+            return content && content.trim().length > 0;
+        }
+        // Headings/Bullets/Quotes must have content
+        const typeMap = { 3: 'heading1', 4: 'heading2', 5: 'heading3', 12: 'bullet', 13: 'ordered', 15: 'quote' };
+        if (block.block_type in typeMap) {
+             const prop = typeMap[block.block_type];
+             const content = block[prop]?.elements?.[0]?.text_run?.content;
+             return content && content.trim().length > 0;
+        }
+        // Code blocks are generally safe even if empty, but better to prevent empty text_run issues
+        if (block.block_type === 14) {
+             const content = block.code?.elements?.[0]?.text_run?.content;
+             // Allow empty code blocks but ensure text_run structure exists
+             // Feishu might reject empty content in text_run, so let's enforce at least a space or filter it.
+             // Filtering empty code blocks is safer for append operations.
+             return content && content.length > 0; 
+        }
+        return true;
+    });
+};
+
+module.exports = {
+    sanitizeMarkdown,
+    validateBlocks
+};