gchq/CyberChef · error · OperationError

Error generating QR code. (${err})

Error message

Error generating QR code. (${err})

What it means

Thrown by generateQrCode when `qr.imageSync` raises — typically because the input string is too long for the selected error-correction level, contains data the qr-image encoder rejects, or an unsupported option combination. The qr-image error is appended.

Source

Thrown at src/core/lib/QRCode.mjs:96

    margin,
    errorCorrection,
) {
    const formats = ["SVG", "EPS", "PDF", "PNG"];
    if (!formats.includes(format.toUpperCase())) {
        throw new OperationError("Unsupported QR code format.");
    }

    let qrImage;
    try {
        qrImage = qr.imageSync(input, {
            type: format,
            size: moduleSize,
            margin: margin,
            // eslint-disable-next-line camelcase
            ec_level: errorCorrection.charAt(0).toUpperCase(),
        });
    } catch (err) {
        throw new OperationError(`Error generating QR code. (${err})`);
    }

    if (!qrImage) {
        throw new OperationError("Error generating QR code.");
    }

    switch (format) {
        case "SVG":
        case "EPS":
        case "PDF":
            return Utils.strToArrayBuffer(qrImage);
        case "PNG":
            return qrImage.buffer.slice(qrImage.byteOffset, qrImage.byteLength + qrImage.byteOffset);
        default:
            throw new OperationError("Unsupported QR code format.");
    }
}

View on GitHub (pinned to 4290ea7539)

Solutions

1. Shorten the input or lower error correction to 'L'.
2. Ensure errorCorrection starts with one of 'L','M','Q','H'.
3. Pass a plain string (convert binary to base64 first if needed).

Example fix

// before
generateQrCode(hugeString, 'PNG', 4, 4, 'H');
// after
generateQrCode(hugeString.slice(0, 1000), 'PNG', 4, 4, 'L');

const EC_LEVELS = new Set(['L','M','Q','H']);
const ec = String(errorCorrection || '').charAt(0).toUpperCase();
if (!EC_LEVELS.has(ec)) throw new Error('Invalid error correction level');
if (typeof input !== 'string' || !input) throw new Error('Input must be a non-empty string');
generateQrCode(input, format, moduleSize, margin, ec);

function isEcLevel(v) {
  return ['L','M','Q','H'].includes(String(v).charAt(0).toUpperCase());
}

try {
  return generateQrCode(input, format, moduleSize, margin, errorCorrection);
} catch (e) {
  if (e instanceof OperationError && /Error generating QR code/.test(e.message)) {
    // shorten input or lower EC to 'L' and retry
  }
  throw e;
}

When it happens

Trigger: Calling generateQrCode with a very long input that exceeds QR capacity at the chosen ec_level; invalid ec_level char (errorCorrection.charAt(0) yields a non-M/L/H/Q letter); passing an object/undefined as input.

Common situations: Encoding a URL or blob over ~2,953 bytes (max for version 40, low EC); feeding binary that qr-image cannot encode; ec_level dropdown misconfigured.

Related errors

• Error generating QR code.
• Error opening image. (${err})
• Could not read a QR code from the image.
• Unsupported QR code format.
• Error normalising image. (${err})

AI-assisted analysis of gchq/CyberChef@4290ea7539 (2026-08-13). Data as JSON: /api/errors/44282770cf71472b. Report an issue: GitHub.