Function clean_nodes

packages/svelte/src/compiler/phases/3-transform/utils.js:126–306

(
	parent,
	nodes,
	path,
	namespace = 'html',
	state,
	// TODO give these defaults (state.options.preserveWhitespace and state.options.preserveComments).
	// first, we need to make `Component(Client|Server)TransformState` inherit from a new `ComponentTransformState`
	// rather than from `ClientTransformState` and `ServerTransformState`
	preserve_whitespace,
	preserve_comments
)

 * @param {boolean} preserve_comments
 */
export function clean_nodes(
	parent,
	nodes,
	path,
	namespace = 'html',
	state,
	// TODO give these defaults (state.options.preserveWhitespace and state.options.preserveComments).
	// first, we need to make `Component(Client|Server)TransformState` inherit from a new `ComponentTransformState`
	// rather than from `ClientTransformState` and `ServerTransformState`
	preserve_whitespace,
	preserve_comments
) {
	if (!state.analysis.runes) {
		nodes = sort_const_tags(nodes, state);
	}

	/** @type {AST.SvelteNode[]} */
	const hoisted = [];

	/** @type {AST.SvelteNode[]} */
	const regular = [];

	for (const node of nodes) {
		if (node.type === 'Comment' && !preserve_comments) {
			continue;
		}

		if (
			node.type === 'ConstTag' ||
			node.type === 'DeclarationTag' ||
			node.type === 'DebugTag' ||
			node.type === 'SvelteBody' ||
			node.type === 'SvelteWindow' ||
			node.type === 'SvelteDocument' ||
			node.type === 'SvelteHead' ||
			node.type === 'TitleElement' ||
			node.type === 'SnippetBlock'
		) {
			// TODO others?
			hoisted.push(node);
		} else {
			regular.push(node);
		}
	}

	let trimmed = regular;

	if (!preserve_whitespace) {
		trimmed = [];

		let first, last;

		while (
			(first = regular[0]) &&
			first.type === 'Text' &&
			!regex_not_whitespace.test(first.data)
		) {
			regular.shift();