attribute_matches() — svelte Function Reference

Source Code

packages/svelte/src/compiler/phases/2-analyze/css/css-prune.js lines 626–735

function attribute_matches(node, name, expected_value, operator, case_insensitive) {
	for (const attribute of node.attributes) {
		if (attribute.type === 'SpreadAttribute') return true;
		if (attribute.type === 'BindDirective' && attribute.name === name) return true;

		const name_lower = name.toLowerCase();
		// match attributes against the corresponding directive but bail out on exact matching
		if (attribute.type === 'StyleDirective' && name_lower === 'style') return true;
		if (attribute.type === 'ClassDirective' && name_lower === 'class') {
			if (operator === '~=') {
				if (attribute.name === expected_value) return true;
			} else {
				return true;
			}
		}

		if (attribute.type !== 'Attribute') continue;
		if (attribute.name.toLowerCase() !== name_lower) continue;

		if (attribute.value === true) return operator === null;
		if (expected_value === null) return true;

		if (is_text_attribute(attribute)) {
			const matches = test_attribute(
				operator,
				expected_value,
				case_insensitive,
				attribute.value[0].data
			);
			// continue if we still may match against a class/style directive
			if (!matches && (name_lower === 'class' || name_lower === 'style')) continue;
			return matches;
		}

		const chunks = get_attribute_chunks(attribute.value);
		const possible_values = new Set();

		/** @type {string[]} */
		let prev_values = [];
		for (const chunk of chunks) {
			const current_possible_values = get_possible_values(chunk, name_lower === 'class');

			// impossible to find out all combinations
			if (!current_possible_values) return true;

			if (prev_values.length > 0) {
				/** @type {string[]} */
				const start_with_space = [];

				/** @type {string[]} */
				const remaining = [];

				current_possible_values.forEach((current_possible_value) => {
					if (regex_starts_with_whitespace.test(current_possible_value)) {
						start_with_space.push(current_possible_value);
					} else {
						remaining.push(current_possible_value);
					}
				});
				if (remaining.length > 0) {
					if (start_with_space.length > 0) {
						prev_values.forEach((prev_value) => possible_values.add(prev_value));
					}

					/** @type {string[]} */
					const combined = [];

					prev_values.forEach((prev_value) => {
						remaining.forEach((value) => {
							combined.push(prev_value + value);
						});
					});
					prev_values = combined;
					start_with_space.forEach((value) => {
						if (regex_ends_with_whitespace.test(value)) {
							possible_values.add(value);
						} else {
							prev_values.push(value);
						}
					});
					continue;