Function formatError

src/platform/node-hyperscript.js:228–252

(filePath, fileContent, error, regionOffset, region)

// ===== Error formatting =====

function formatError(filePath, fileContent, error, regionOffset, region) {
    // Map error position to absolute file position
    const absOffset = regionOffset + (error.token?.start ?? 0);
    const pos = offsetToLineCol(fileContent, absOffset);
    const relPath = path.relative(process.cwd(), filePath);

    let out = `\x1b[1m${relPath}:${pos.line}:${pos.col}\x1b[0m \x1b[31merror:\x1b[0m ${error.message}`;

    // Show context line
    const lines = fileContent.split('\n');
    const lineIdx = pos.line - 1;
    if (lineIdx >= 0 && lineIdx < lines.length) {
        const lineStr = lines[lineIdx];
        const gutter = String(pos.line).length;
        out += '\n';
        out += `  ${String(pos.line).padStart(gutter)} | ${lineStr}\n`;

        // Underline
        const col = pos.col - 1;
        const len = Math.max(1, error.token?.value?.length || 1);
        out += `  ${' '.repeat(gutter)} | ${' '.repeat(col)}${'~'.repeat(len)}`;
    }

    return out;
}

function offsetToLineCol(text, offset) {
    let line = 1, col = 1;