sveltejs/svelte · error · Error

set_context_after_init

set_context_after_init

Error message

set_context_after_init
`setContext` must be called when a component first initializes, not in a subsequent effect or after an `await` expression
https://svelte.dev/e/set_context_after_init

What it means

Thrown at internal/client/context.js:138 (only in async mode) when setContext is called outside the synchronous component-initialisation window — specifically when there is an active reaction, or the branch-effect/pop() flags indicate the call happens after an await boundary or inside a later effect. Context in Svelte is tied to component init; setting it later would make it unavailable to the synchronous render of children.

Source

Thrown at packages/svelte/src/internal/client/errors.js:444

		throw error;
	} else {
		throw new Error(`https://svelte.dev/e/rune_outside_svelte`);
	}
}

/**
 * `setContext` must be called when a component first initializes, not in a subsequent effect or after an `await` expression
 * @returns {never}
 */
export function set_context_after_init() {
	if (DEV) {
		const error = new Error(`set_context_after_init\n\`setContext\` must be called when a component first initializes, not in a subsequent effect or after an \`await\` expression\nhttps://svelte.dev/e/set_context_after_init`);

		error.name = 'Svelte error';

		throw error;
	} else {
		throw new Error(`https://svelte.dev/e/set_context_after_init`);
	}
}

/**
 * Property descriptors defined on `$state` objects must contain `value` and always be `enumerable`, `configurable` and `writable`.
 * @returns {never}
 */
export function state_descriptors_fixed() {
	if (DEV) {
		const error = new Error(`state_descriptors_fixed\nProperty descriptors defined on \`$state\` objects must contain \`value\` and always be \`enumerable\`, \`configurable\` and \`writable\`.\nhttps://svelte.dev/e/state_descriptors_fixed`);

		error.name = 'Svelte error';

		throw error;
	} else {
		throw new Error(`https://svelte.dev/e/state_descriptors_fixed`);
	}
}

View on GitHub (pinned to 20b341f100)

Solutions

1. Call setContext synchronously at the top of the component body, before any await or effect.
2. If the context value depends on async data, set a placeholder synchronously and update the reactive contents later rather than delaying setContext itself.
3. Move async work into an effect and store results in $state; keep context registration synchronous.

Example fix

// before
let data = await fetchThing();
setContext('thing', data); // after await -> throws

// after
setContext('thing', {}); // synchronously
let data = $state();
onMount(async () => { data = await fetchThing(); });

// Call setContext synchronously at the top of the component body, before any await.
// If the value depends on async data, register context synchronously and update contents later:
// setContext('key', {});
// onMount(async () => { Object.assign(getContext('key'), await load()); });

When it happens

Trigger: Calling setContext after an `await` inside component setup, inside a $effect, inside a then()/setTimeout callback, or after the initial synchronous component body has completed. The guard at context.js:129-139 checks active_reaction and the component context 'i' (pop) flag.

Common situations: Awaiting data then calling setContext; setting context inside onMount/$effect; refactor that moved setContext into an async function; top-level await in component script.

Related errors

• effect_orphan
• get_abort_signal_outside_reaction
• lifecycle_legacy_only
• lifecycle_outside_component
• async_derived_orphan

AI-assisted analysis of sveltejs/svelte@20b341f100 (2026-08-12). Data as JSON: /api/errors/eeada3096e2611c6. Report an issue: GitHub.