denoland/deno · error · RangeError

Cannot enqueue value with size: chunk size is invalid

Error message

Cannot enqueue value with size: chunk size is invalid

What it means

The second guard in enqueueValueWithSize (ext/web/06_streams.js:707-711): if the strategy's size() returns exactly Infinity, RangeError 'Cannot enqueue value with size: chunk size is invalid' is thrown, because an infinite chunk size would poison the queue's queueTotalSize arithmetic. This is required streams-spec behavior. Typical cause is a custom size function that divides by zero or deliberately returns Infinity trying to 'disable backpressure'.

Source

Thrown at ext/web/06_streams.js:708

  }
  return node.value;
}
/**
 * @template T
 * @param {{ [_queue]: Array<ValueWithSize<T | _close>>, [_queueTotalSize]: number }} container
 * @param {T} value
 * @param {number} size
 * @returns {void}
 */
function enqueueValueWithSize(container, value, size) {
  assert(container[_queue] && typeof container[_queueTotalSize] === "number");
  if (isNonNegativeNumber(size) === false) {
    throw new RangeError(
      "Cannot enqueue value with size: chunk size must be a positive number",
    );
  }
  if (size === Infinity) {
    throw new RangeError(
      "Cannot enqueue value with size: chunk size is invalid",
    );
  }
  container[_queue].enqueueWithSize(value, size);
  container[_queueTotalSize] += size;
}

/**
 * @param {QueuingStrategy} strategy
 * @param {number} defaultHWM
 */
function extractHighWaterMark(strategy, defaultHWM) {
  if (strategy.highWaterMark === undefined) {
    return defaultHWM;
  }
  const highWaterMark = strategy.highWaterMark;
  if (NumberIsNaN(highWaterMark) || highWaterMark < 0) {
    throw new RangeError(

View on GitHub (pinned to 9ad36f7a2c)

Solutions

1. Clamp the size to a large finite value: Math.min(size, Number.MAX_SAFE_INTEGER).
2. If the goal is 'no backpressure', omit size and pass a large finite highWaterMark instead.
3. Guard division: size: (c) => count === 0 ? 1 : c.byteLength / count.
4. Test size() against zero-denominator and empty-chunk cases.

Example fix

// before
new WritableStream(sink, { size: () => Infinity }); // RangeError: chunk size is invalid

// after
new WritableStream(sink, { size: () => Number.MAX_SAFE_INTEGER });

const size = (c) => {
  const n = compute(c);
  return Number.isFinite(n) ? Math.max(0, n) : Number.MAX_SAFE_INTEGER;
};
new WritableStream(sink, { size });

const isValidChunkSize = (n) =>
  typeof n === 'number' && !Number.isNaN(n) && n >= 0 && n !== Infinity;

try {
  await writer.write(chunk);
} catch (e) {
  if (e instanceof RangeError && e.message.includes('chunk size is invalid')) {
    await writer.write(chunk); // after clamping size()
  } else throw e;
}

When it happens

Trigger: new WritableStream(sink, { size: () => Infinity }) followed by a write; size: (c) => c.byteLength / count with count === 0; any size computation that overflows or intentionally yields Infinity.

Common situations: Developers trying to bypass backpressure by returning Infinity from size; ratio-based size math with a zero denominator; sizes derived from unbounded inputs.

Related errors

• Cannot enqueue value with size: chunk size must be a positiv
• Expected highWaterMark to be a positive number or Infinity,
• Response body is already used
• Value must be a positive bigint: received ${value}
• Value must fit in a 64-bit unsigned integer

AI-assisted analysis of denoland/deno@9ad36f7a2c (2026-08-20). Data as JSON: /api/errors/4874f68a9ff9f4a5. Report an issue: GitHub.