denoland/deno · error · RangeError

Failed to construct 'QuotaExceededError': quota must not be

Error message

Failed to construct 'QuotaExceededError': quota must not be negative

What it means

QuotaExceededError (ext/web/01_dom_exception.js:285, defined per WebIDL 4.3.1) is constructible in Deno with an options bag exposing quota/requested details. The 'quota' member is converted to an unrestricted double and must not be negative; a negative value throws this RangeError from the constructor, so the exception object is never produced.

Source

Thrown at ext/web/01_dom_exception.js:285

// Defined in WebIDL 4.3.1.
// https://webidl.spec.whatwg.org/#quotaexceedederror
class QuotaExceededError extends DOMException {
  [_quota];
  [_requested];

  constructor(message = "", options = { __proto__: null }) {
    super(message, "QuotaExceededError");

    if (options !== null && typeof options === "object") {
      if (ObjectHasOwn(options, "quota")) {
        const quota = webidl.converters["unrestricted double"](
          options.quota,
          "Failed to construct 'QuotaExceededError'",
          "'quota' member of QuotaExceededErrorOptions",
        );
        if (quota < 0) {
          throw new RangeError(
            "Failed to construct 'QuotaExceededError': quota must not be negative",
          );
        }
        this[_quota] = quota;
      } else {
        this[_quota] = null;
      }
      if (ObjectHasOwn(options, "requested")) {
        const requested = webidl.converters["unrestricted double"](
          options.requested,
          "Failed to construct 'QuotaExceededError'",
          "'requested' member of QuotaExceededErrorOptions",
        );
        if (requested < 0) {
          throw new RangeError(
            "Failed to construct 'QuotaExceededError': requested must not be negative",
          );
        }

View on GitHub (pinned to 9ad36f7a2c)

Solutions

Omit the quota member when unknown; it defaults to null
Clamp before constructing: Math.max(0, quota)
Validate the options bag with a guard so callers get your own error message instead of the constructor's

Example fix

// before
throw new QuotaExceededError('storage full', { quota: limit - used }); // can be -1

// after
throw new QuotaExceededError('storage full', {
  quota: Math.max(0, limit - used),
});

Defensive patterns

Strategy: validation

Validate before calling

if (quota !== undefined && !(typeof quota === "number" && quota >= 0)) {
  throw new RangeError("quota must be a non-negative number");
}
throw new QuotaExceededError(msg, { quota });

Type guard

const isNonNegativeNumber = (v: unknown): v is number =>
  typeof v === "number" && Number.isFinite(v) && v >= 0;

Try / catch

try {
  throw new QuotaExceededError(msg, options);
} catch (e) {
  if (e instanceof RangeError && e.message.includes("quota must not be negative")) {
    throw new QuotaExceededError(msg); // omit the details member
  }
  throw e;
}

Prevention

Clamp computed quota values with Math.max(0, x)
Use null/omission instead of -1 sentinels for unknown quota
Validate the whole options bag once before constructing the error

When it happens

Trigger: new QuotaExceededError('msg', { quota: -1 }); quota computed as limit - used underflowing below zero; passing a -1 sentinel meaning 'unknown'; forwarding unvalidated user input into the options bag.

Common situations: Wrapping storage/quota reporting APIs (e.g. navigator.storage.estimate style flows) that surface a QuotaExceededError with details; libraries using negative sentinels for missing values; unit tests probing constructor validation.

Related errors

AI-assisted analysis of denoland/deno@9ad36f7a2c (2026-08-20). Data as JSON: /api/errors/55c6672664a50ba5. Report an issue: GitHub.