Function update_reaction

packages/svelte/src/internal/client/runtime.js:223–356

(reaction)

/** @param {Reaction} reaction */
export function update_reaction(reaction) {
	var previous_deps = new_deps;
	var previous_skipped_deps = skipped_deps;
	var previous_untracked_writes = untracked_writes;
	var previous_reaction = active_reaction;
	var previous_sources = current_sources;
	var previous_component_context = component_context;
	var previous_untracking = untracking;
	var previous_update_version = update_version;

	var flags = reaction.f;

	new_deps = /** @type {null | Value[]} */ (null);
	skipped_deps = 0;
	untracked_writes = null;
	active_reaction = (flags & (BRANCH_EFFECT | ROOT_EFFECT)) === 0 ? reaction : null;

	current_sources = null;
	set_component_context(reaction.ctx);
	untracking = false;
	update_version = ++read_version;

	if (reaction.ac !== null) {
		without_reactive_context(() => {
			/** @type {AbortController} */ (reaction.ac).abort(STALE_REACTION);
		});

		reaction.ac = null;
	}

	try {
		reaction.f |= REACTION_IS_UPDATING;
		var fn = /** @type {Function} */ (reaction.fn);
		var result = fn();
		reaction.f |= REACTION_RAN;
		var deps = reaction.deps;

		// Don't remove reactions during fork;
		// they must remain for when fork is discarded
		var is_fork = current_batch?.is_fork;

		if (new_deps !== null) {
			var i;

			if (!is_fork) {
				remove_reactions(reaction, skipped_deps);
			}

			if (deps !== null && skipped_deps > 0) {
				deps.length = skipped_deps + new_deps.length;
				for (i = 0; i < new_deps.length; i++) {
					deps[skipped_deps + i] = new_deps[i];
				}
			} else {
				reaction.deps = deps = new_deps;
			}

			if (effect_tracking() && (reaction.f & CONNECTED) !== 0) {