denoland/deno · error · RangeError

Failed to construct 'QuotaExceededError': requested must not

Error message

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

What it means

The second validated member of QuotaExceededErrorOptions (ext/web/01_dom_exception.js:300): 'requested' is converted to an unrestricted double and rejected when negative. The RangeError is thrown from the constructor after quota was already processed, so a negative 'requested' alone is enough to abort construction of the DOMException subclass.

Source

Thrown at ext/web/01_dom_exception.js:300

          "'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",
          );
        }
        this[_requested] = requested;
      } else {
        this[_requested] = null;
      }
    } else {
      this[_quota] = null;
      this[_requested] = null;
    }
  }

  get quota() {
    webidl.assertBranded(this, QuotaExceededErrorPrototype);
    return this[_quota];
  }

View on GitHub (pinned to 9ad36f7a2c)

Solutions

Omit requested when unknown; it defaults to null
Clamp: Math.max(0, requested)
Validate both quota and requested together before constructing the error

Example fix

// before
throw new QuotaExceededError('quota hit', { requested: req }); // req = -1 on error

// after
throw new QuotaExceededError('quota hit', {
  requested: req >= 0 ? req : 0,
});

Defensive patterns

Strategy: validation

Validate before calling

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

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("requested must not be negative")) {
    throw new QuotaExceededError(msg); // omit the details member
  }
  throw e;
}

Prevention

Clamp requested sizes with Math.max(0, x) before constructing the error
Omit the requested member when the failed write size is unknown
Validate quota and requested with one shared guard in error-reporting code

When it happens

Trigger: new QuotaExceededError('msg', { requested: -1 }); requested derived from a size measurement that failed and defaulted to a negative sentinel; passing through caller-supplied sizes unvalidated.

Common situations: Reporting how many bytes a failed write requested when the measurement errors out; -1 sentinels from C-style APIs leaking into the options bag; tests constructing the error with edge-case numbers.

Related errors

AI-assisted analysis of denoland/deno@9ad36f7a2c (2026-08-20). Data as JSON: /api/errors/0953432609ef70c9. Report an issue: GitHub.