What causes "Query resolved without a value" in sveltejs/kit?

Ensure the remote query function always returns a value for every code path

sveltejs/kit · error · HandledHttpError

Query resolved without a value

Error message

Query resolved without a value

What it means

A Query's promise resolves only when the query has a value (#ready). If the underlying promise settles but no value was ever set, the client throws a HandledHttpError (500 by default, or the stored #error), meaning the query resolved without producing a value.

Source

Thrown at packages/kit/src/runtime/client/remote-functions/query/instance.svelte.js:54

		// don't reduce undefined value
		if (!this.#ready) return undefined;

		return this.#overrides.reduce((v, r) => r(v), /** @type {T} */ (this.#raw));
	});

	/** @type {App.Error | undefined} */
	#error = $state.raw(undefined);

	/** @type {Promise<T>['then']} */
	// @ts-expect-error TS doesn't understand that the promise returns something
	#then = $derived.by(() => {
		const p = this.#get_promise();
		this.#overrides.length;

		return (resolve, reject) => {
			const result = p.then(tick).then(() => {
				if (!this.#ready) {
					throw new HandledHttpError(
						this.#error ?? { status: 500, message: 'Query resolved without a value' }
					);
				}

				return /** @type {T} */ (this.#current);
			});

			if (resolve || reject) {
				return result.then(resolve, reject);
			}

			return result;
		};
	});

	/**
	 * @param {string} key
	 * @param {() => Promise<T>} fn

View on GitHub (pinned to 03f1687fe6)

Solutions

Ensure the remote query function always returns a value for every code path
Check the server handler for early returns/undefined results and add logging
Inspect overrides/cancel logic so a query is not left in a non-ready settled state
Update @sveltejs/kit — resolution handling in queries changed across releases

Example fix

// before
export const getUser = query(async (id) => {
  if (!id) return; // resolves without a value
  return db.users.get(id);
});
// after
export const getUser = query(async (id) => {
  if (!id) error(400, 'id required');
  return db.users.get(id);
});

Defensive patterns

Strategy: try-catch

Try / catch

try {
  const value = await userQuery;
} catch (e) {
  // HandledHttpError — Query resolved without a value
  showFallback(e.status ?? 500);
}

Prevention

Ensure remote query functions return a value on every path
Use error(...) instead of bare returns for invalid input
Test all conditional branches of remote query functions

When it happens

Trigger: The remote query function's returned promise resolved without the query instance receiving a value — e.g. the server handler returned undefined, an override was applied without a value, or the query errored in a way that left #error unset and #ready false when the awaited chain completed.

Common situations: Remote query function that conditionally returns nothing; awaiting a query that was never properly started; race where an error/override path skipped setting the current value; server bug returning an empty result the client can't adopt.

Related errors

AI-assisted analysis of sveltejs/kit@03f1687fe6 (2026-09-02). Data as JSON: /api/errors/1a7ffea361bf8ad8. Report an issue: GitHub.