set_custom_element_data() — svelte Function Reference

Source Code

packages/svelte/src/internal/client/dom/elements/attributes.js lines 216–263

export function set_custom_element_data(node, prop, value) {
	// We need to ensure that setting custom element props, which can
	// invoke lifecycle methods on other custom elements, does not also
	// associate those lifecycle methods with the current active reaction
	// or effect
	var previous_reaction = active_reaction;
	var previous_effect = active_effect;

	// If we're hydrating but the custom element is from Svelte, and it already scaffolded,
	// then it might run block logic in hydration mode, which we have to prevent.
	let was_hydrating = hydrating;
	if (hydrating) {
		set_hydrating(false);
	}

	set_active_reaction(null);
	set_active_effect(null);

	try {
		if (
			// `style` should use `set_attribute` rather than the setter
			prop !== 'style' &&
			// Don't compute setters for custom elements while they aren't registered yet,
			// because during their upgrade/instantiation they might add more setters.
			// Instead, fall back to a simple "an object, then set as property" heuristic.
			(setters_cache.has(node.getAttribute('is') || node.nodeName) ||
			// customElements may not be available in browser extension contexts
			!customElements ||
			customElements.get(node.getAttribute('is') || node.tagName.toLowerCase())
				? get_setters(node).includes(prop)
				: value && typeof value === 'object')
		) {
			// @ts-expect-error
			node[prop] = value;
		} else {
			// We did getters etc checks already, stringify before passing to set_attribute
			// to ensure it doesn't invoke the same logic again, and potentially populating
			// the setters cache too early.
			set_attribute(node, prop, value == null ? value : String(value));
		}
	} finally {
		set_active_reaction(previous_reaction);
		set_active_effect(previous_effect);
		if (was_hydrating) {
			set_hydrating(true);
		}
	}
}