From 22656696af5417396b69ab10b6b3b2bc1c79ee5e Mon Sep 17 00:00:00 2001
From: Maksim Kostromin <daggerok@gmail.com>
Date: Sat, 24 Oct 2026 23:33:25 -0400
Subject: [PATCH] fix(parser): avoid Math.max spread on large files

Math.max(...rows.map(r => r.length)) passes one argument per row and throws Maximum call stack size exceeded in V8 somewhere between 100k and 200k rows, so large files failed to load and the merged export failed. A maxRowLength loop helper replaces the spreads in extractValidTableData and the merged export width, and the existing reduce in applyFilters.
---
 src/main.tsx | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/main.tsx b/src/main.tsx
index 00921e4..8b0c7b8 100644
--- a/src/main.tsx
+++ b/src/main.tsx
@@ -403,6 +403,13 @@ function parseCSVText(text: string): string[][] {
     return rows;
 }
 
+/** Longest row length. A loop, not Math.max(...rows): spreading ~150k+ arguments overflows the V8 stack. */
+function maxRowLength(rows: readonly (readonly unknown[])[], min = 0): number {
+    let max = min;
+    for (const row of rows) if (row.length > max) max = row.length;
+    return max;
+}
+
 function extractValidTableData(rawText: string): string[][] {
     const parsedLines = parseCSVText(rawText).filter(row => row.some(cell => cell !== ''));
     if (parsedLines.length === 0) return [];
@@ -412,7 +419,7 @@ function extractValidTableData(rawText: string): string[][] {
     for (const [lengthStr, count] of Object.entries(colCounts)) {
         if (count > maxOccurrences) { maxOccurrences = count; targetColLength = parseInt(lengthStr, 10); }
     }
-    if (targetColLength === 0) targetColLength = Math.max(...parsedLines.map(r => r.length));
+    if (targetColLength === 0) targetColLength = maxRowLength(parsedLines);
     // Rows one field shorter belong to the table too: Fidelity data rows end with a comma, so the
     // header has one field less than every data row and used to be dropped. Rows are padded, never cut
     const tableData: string[][] = [];
@@ -426,7 +433,7 @@ function extractValidTableData(rawText: string): string[][] {
         } else if (isRecording && row.length < targetColLength - 1) { break; }
     }
     if (tableData.length === 0) return parsedLines;
-    let width = Math.max(...tableData.map(r => r.length));
+    let width = maxRowLength(tableData);
     // a trailing column that is empty in every row (the trailing comma) is not a column
     while (width > 1 && tableData.every(r => (r[width - 1] ?? '') === '')) width--;
     return tableData.map(r => (r.length >= width ? r.slice(0, width) : [...r, ...Array.from({ length: width - r.length }, () => '')]));
@@ -610,7 +617,7 @@ function applyFilters(rows: string[][], filters: Record<number, string>, getColT
         const ci = parseInt(s, 10); const ct = getColType(ci); const ex = parseFilterExpression(f, ct);
         if (ex) parsed.push({ colIndex: ci, expression: ex, colType: ct });
     }
-    const width = rows.reduce((max, row) => Math.max(max, row.length), 0);
+    const width = maxRowLength(rows);
     const usable = parsed.filter(({ colIndex }) => colIndex < width);
     if (usable.length === 0) return rows;
     return rows.filter(row => usable.every(({ colIndex, expression, colType }) => matchesFilter(row[colIndex] || '', expression, colType)));
@@ -1552,14 +1559,7 @@ const App: React.FC = () => {
             return { fileName: dataset.fileName, headers, rows: sorted };
         });
 
-        const maxCols = Math.max(
-            1,
-            ...blocks.map(block => Math.max(
-                block.headers.length,
-                ...block.rows.map(r => r.length),
-                1
-            ))
-        );
+        const maxCols = blocks.reduce((max, block) => Math.max(max, block.headers.length, maxRowLength(block.rows)), 1);
 
         const mergedRows: string[][] = [];
         for (const block of blocks) {