optimize `parser.*` calls

src/compiler/parse/read/style.ts

@@ -5,10 +5,12 @@ import { Node } from 'estree';
 import { Style } from '../../interfaces';
 import parser_errors from '../errors';
 
+const regex_closing_style_tag = /<\/style\s*>/;
+
 export default function read_style(parser: Parser, start: number, attributes: Node[]): Style {
 	const content_start = parser.index;
 
-	const styles = parser.read_until(/<\/style\s*>/, parser_errors.unclosed_style);
+	const styles = parser.read_until(regex_closing_style_tag, parser_errors.unclosed_style);
 
 	if (parser.index >= parser.template.length) {
 		parser.error(parser_errors.unclosed_style);
@@ -67,7 +69,7 @@ export default function read_style(parser: Parser, start: number, attributes: No
 		}
 	});
 
-	parser.read(/<\/style\s*>/);
+	parser.read(regex_closing_style_tag);
 	const end = parser.index;
 
 	return {

src/compiler/parse/state/mustache.ts

@@ -33,6 +33,8 @@ function trim_whitespace(block: TemplateNode, trim_before: boolean, trim_after:
 	}
 }
 
+const regex_whitespace_with_closing_curly_brace = /\s*}/;
+
 export default function mustache(parser: Parser) {
 	const start = parser.index;
 	parser.index += 1;
@@ -290,7 +292,7 @@ export default function mustache(parser: Parser) {
 
 		const await_block_shorthand = type === 'AwaitBlock' && parser.eat('then');
 		if (await_block_shorthand) {
-			if (parser.match_regex(/\s*}/)) {
+			if (parser.match_regex(regex_whitespace_with_closing_curly_brace)) {
 				parser.allow_whitespace();
 			} else {
 				parser.require_whitespace();
@@ -301,7 +303,7 @@ export default function mustache(parser: Parser) {
 
 		const await_block_catch_shorthand = !await_block_shorthand && type === 'AwaitBlock' && parser.eat('catch');
 		if (await_block_catch_shorthand) {
-			if (parser.match_regex(/\s*}/)) {
+			if (parser.match_regex(regex_whitespace_with_closing_curly_brace)) {
 				parser.allow_whitespace();
 			} else {
 				parser.require_whitespace();
@@ -350,7 +352,7 @@ export default function mustache(parser: Parser) {
 		let identifiers;
 
 		// Implies {@debug} which indicates "debug all"
-		if (parser.read(/\s*}/)) {
+		if (parser.read(regex_whitespace_with_closing_curly_brace)) {
 			identifiers = [];
 		} else {
 			const expression = read_expression(parser);

src/compiler/parse/state/tag.ts

@@ -53,13 +53,16 @@ function parent_is_head(stack) {
 	return false;
 }
 
+const regex_closing_textarea_tag = /^<\/textarea(\s[^>]*)?>/i;
+const regex_closing_comment = /-->/;
+
 export default function tag(parser: Parser) {
 	const start = parser.index++;
 
 	let parent = parser.current();
 
 	if (parser.eat('!--')) {
-		const data = parser.read_until(/-->/);
+		const data = parser.read_until(regex_closing_comment);
 		parser.eat('-->', true, parser_errors.unclosed_comment);
 
 		parser.current().children.push({
@@ -218,11 +221,10 @@ export default function tag(parser: Parser) {
 		// special case
 		element.children = read_sequence(
 			parser,
-			() =>
+			() => regex_closing_textarea_tag.test(parser.template.slice(parser.index)),
-				/^<\/textarea(\s[^>]*)?>/i.test(parser.template.slice(parser.index)),
 			'inside <textarea>'
 		);
-		parser.read(/^<\/textarea(\s[^>]*)?>/i);
+		parser.read(regex_closing_textarea_tag);
 		element.end = parser.index;
 	} else if (name === 'script' || name === 'style') {
 		// special case
@@ -237,6 +239,8 @@ export default function tag(parser: Parser) {
 	}
 }
 
+const regex_whitespace_or_slash_or_closing_tag = /(\s|\/|>)/;
+
 function read_tag_name(parser: Parser) {
 	const start = parser.index;
 
@@ -266,7 +270,7 @@ function read_tag_name(parser: Parser) {
 
 	if (parser.read(SLOT)) return 'svelte:fragment';
 
-	const name = parser.read_until(/(\s|\/|>)/);
+	const name = parser.read_until(regex_whitespace_or_slash_or_closing_tag);
 
 	if (meta_tags.has(name)) return name;
 
@@ -286,6 +290,10 @@ function read_tag_name(parser: Parser) {
 	return name;
 }
 
+// eslint-disable-next-line no-useless-escape
+const regex_token_ending_character = /[\s=\/>"']/;
+const regex_quote_characters = /["']/;
+
 function read_attribute(parser: Parser, unique_names: Set<string>) {
 	const start = parser.index;
 
@@ -344,8 +352,7 @@ function read_attribute(parser: Parser, unique_names: Set<string>) {
 		}
 	}
 
-	// eslint-disable-next-line no-useless-escape
+	const name = parser.read_until(regex_token_ending_character);
-	const name = parser.read_until(/[\s=\/>"']/);
 	if (!name) return null;
 
 	let end = parser.index;
@@ -360,7 +367,7 @@ function read_attribute(parser: Parser, unique_names: Set<string>) {
 		parser.allow_whitespace();
 		value = read_attribute_value(parser);
 		end = parser.index;
-	} else if (parser.match_regex(/["']/)) {
+	} else if (parser.match_regex(regex_quote_characters)) {
 		parser.error(parser_errors.unexpected_token('='), parser.index);
 	}