perf!: use switch for type_name and remove TYPE_NAMES

README.md

@@ -215,14 +215,14 @@ for (const token of tokenize('a { color: red }')) {
 
 ### Node types, type guards and `clone()`
 
-Node type constants (`STYLE_RULE`, `DECLARATION`, `DIMENSION`, …), `TYPE_NAMES` and `NODE_TYPES` are exported from the root, as are type guards such as `is_declaration()` and `is_dimension()` that narrow a node to its specific type. `node.clone({ deep?, locations? })` returns a mutable plain-object copy of a node.
+Node type constants (`STYLE_RULE`, `DECLARATION`, `DIMENSION`, …) and `NODE_TYPES` are exported from the root, as are type guards such as `is_declaration()` and `is_dimension()` that narrow a node to its specific type. `node.clone({ deep?, locations? })` returns a mutable plain-object copy of a node.
 
 ```typescript
-import { parse, is_declaration, TYPE_NAMES, DECLARATION } from '@projectwallace/css-parser'
+import { parse, is_declaration } from '@projectwallace/css-parser'
 
 const decl = parse('a { color: red }').first_child.block.first_child
 is_declaration(decl) // true
-TYPE_NAMES[DECLARATION] // "Declaration"
+decl.type_name // "Declaration"
 decl.clone({ deep: false }).property // "color"
 ```
 

src/css-node.ts

@@ -72,57 +72,54 @@ import {
 } from './string-utils'
 import { dimension_number_end } from './parse-dimension'
 
-// Type name lookup table - maps numeric type to CSSTree-compatible strings
-export const TYPE_NAMES = {
-	[STYLESHEET]: 'StyleSheet',
-	[STYLE_RULE]: 'Rule',
-	[AT_RULE]: 'Atrule',
-	[DECLARATION]: 'Declaration',
-	[SELECTOR]: 'Selector',
-	[COMMENT]: 'Comment',
-	[BLOCK]: 'Block',
-	[RAW]: 'Raw',
-	[IDENTIFIER]: 'Identifier',
-	[NUMBER]: 'Number',
-	[DIMENSION]: 'Dimension',
-	[STRING]: 'String',
-	[HASH]: 'Hash',
-	[FUNCTION]: 'Function',
-	[OPERATOR]: 'Operator',
-	[PARENTHESIS]: 'Parentheses',
-	[URL]: 'Url',
-	[UNICODE_RANGE]: 'UnicodeRange',
-	[VALUE]: 'Value',
-	[SELECTOR_LIST]: 'SelectorList',
-	[TYPE_SELECTOR]: 'TypeSelector',
-	[CLASS_SELECTOR]: 'ClassSelector',
-	[ID_SELECTOR]: 'IdSelector',
-	[ATTRIBUTE_SELECTOR]: 'AttributeSelector',
-	[PSEUDO_CLASS_SELECTOR]: 'PseudoClassSelector',
-	[PSEUDO_ELEMENT_SELECTOR]: 'PseudoElementSelector',
-	[COMBINATOR]: 'Combinator',
-	[UNIVERSAL_SELECTOR]: 'UniversalSelector',
-	[NESTING_SELECTOR]: 'NestingSelector',
-	[NTH_SELECTOR]: 'Nth',
-	[NTH_OF_SELECTOR]: 'NthOf',
-	[LANG_SELECTOR]: 'Lang',
-	[MEDIA_QUERY]: 'MediaQuery',
-	[MEDIA_FEATURE]: 'Feature',
-	[MEDIA_TYPE]: 'MediaType',
-	[CONTAINER_QUERY]: 'ContainerQuery',
-	[SUPPORTS_QUERY]: 'SupportsQuery',
-	[SUPPORTS_DECLARATION]: 'SupportsDeclaration',
-	[LAYER_NAME]: 'Layer',
-	[PRELUDE_OPERATOR]: 'Operator',
-	[FEATURE_RANGE]: 'MediaFeatureRange',
-	[AT_RULE_PRELUDE]: 'AtrulePrelude',
-	[PRELUDE_SELECTORLIST]: 'PreludeSelectorList',
-	[RATIO]: 'Ratio',
-	[IF_BRANCH]: 'IfBranch',
-	[IF_CONDITION]: 'IfCondition',
-} as const
-
-export type TypeName = (typeof TYPE_NAMES)[keyof typeof TYPE_NAMES] | 'unknown'
+// CSSTree-compatible node type names
+export type TypeName =
+	| 'StyleSheet'
+	| 'Rule'
+	| 'Atrule'
+	| 'Declaration'
+	| 'Selector'
+	| 'Comment'
+	| 'Block'
+	| 'Raw'
+	| 'Identifier'
+	| 'Number'
+	| 'Dimension'
+	| 'String'
+	| 'Hash'
+	| 'Function'
+	| 'Operator'
+	| 'Parentheses'
+	| 'Url'
+	| 'UnicodeRange'
+	| 'Value'
+	| 'SelectorList'
+	| 'TypeSelector'
+	| 'ClassSelector'
+	| 'IdSelector'
+	| 'AttributeSelector'
+	| 'PseudoClassSelector'
+	| 'PseudoElementSelector'
+	| 'Combinator'
+	| 'UniversalSelector'
+	| 'NestingSelector'
+	| 'Nth'
+	| 'NthOf'
+	| 'Lang'
+	| 'MediaQuery'
+	| 'Feature'
+	| 'MediaType'
+	| 'ContainerQuery'
+	| 'SupportsQuery'
+	| 'SupportsDeclaration'
+	| 'Layer'
+	| 'MediaFeatureRange'
+	| 'AtrulePrelude'
+	| 'PreludeSelectorList'
+	| 'Ratio'
+	| 'IfBranch'
+	| 'IfCondition'
+	| 'unknown'
 
 // Node type constants (numeric for performance)
 export type CSSNodeType =
@@ -327,7 +324,103 @@ export class CSSNode {
 
 	/** Get node type as human-readable string */
 	get type_name(): TypeName {
-		return TYPE_NAMES[this.type] || 'unknown'
+		// A switch compiles to a jump table, which is faster than an object lookup
+		switch (this.type) {
+			case STYLESHEET:
+				return 'StyleSheet'
+			case STYLE_RULE:
+				return 'Rule'
+			case AT_RULE:
+				return 'Atrule'
+			case DECLARATION:
+				return 'Declaration'
+			case SELECTOR:
+				return 'Selector'
+			case COMMENT:
+				return 'Comment'
+			case BLOCK:
+				return 'Block'
+			case RAW:
+				return 'Raw'
+			case IDENTIFIER:
+				return 'Identifier'
+			case NUMBER:
+				return 'Number'
+			case DIMENSION:
+				return 'Dimension'
+			case STRING:
+				return 'String'
+			case HASH:
+				return 'Hash'
+			case FUNCTION:
+				return 'Function'
+			case OPERATOR:
+				return 'Operator'
+			case PARENTHESIS:
+				return 'Parentheses'
+			case URL:
+				return 'Url'
+			case UNICODE_RANGE:
+				return 'UnicodeRange'
+			case VALUE:
+				return 'Value'
+			case SELECTOR_LIST:
+				return 'SelectorList'
+			case TYPE_SELECTOR:
+				return 'TypeSelector'
+			case CLASS_SELECTOR:
+				return 'ClassSelector'
+			case ID_SELECTOR:
+				return 'IdSelector'
+			case ATTRIBUTE_SELECTOR:
+				return 'AttributeSelector'
+			case PSEUDO_CLASS_SELECTOR:
+				return 'PseudoClassSelector'
+			case PSEUDO_ELEMENT_SELECTOR:
+				return 'PseudoElementSelector'
+			case COMBINATOR:
+				return 'Combinator'
+			case UNIVERSAL_SELECTOR:
+				return 'UniversalSelector'
+			case NESTING_SELECTOR:
+				return 'NestingSelector'
+			case NTH_SELECTOR:
+				return 'Nth'
+			case NTH_OF_SELECTOR:
+				return 'NthOf'
+			case LANG_SELECTOR:
+				return 'Lang'
+			case MEDIA_QUERY:
+				return 'MediaQuery'
+			case MEDIA_FEATURE:
+				return 'Feature'
+			case MEDIA_TYPE:
+				return 'MediaType'
+			case CONTAINER_QUERY:
+				return 'ContainerQuery'
+			case SUPPORTS_QUERY:
+				return 'SupportsQuery'
+			case SUPPORTS_DECLARATION:
+				return 'SupportsDeclaration'
+			case LAYER_NAME:
+				return 'Layer'
+			case PRELUDE_OPERATOR:
+				return 'Operator'
+			case FEATURE_RANGE:
+				return 'MediaFeatureRange'
+			case AT_RULE_PRELUDE:
+				return 'AtrulePrelude'
+			case PRELUDE_SELECTORLIST:
+				return 'PreludeSelectorList'
+			case RATIO:
+				return 'Ratio'
+			case IF_BRANCH:
+				return 'IfBranch'
+			case IF_CONDITION:
+				return 'IfCondition'
+			default:
+				return 'unknown'
+		}
 	}
 
 	/** Get the full text of this node from source */

src/index.ts

@@ -21,7 +21,7 @@ export {
 export { type ParserOptions } from './parse'
 
 // Types
-export { TYPE_NAMES, type CloneOptions, type PlainCSSNode } from './css-node'
+export { type CloneOptions, type PlainCSSNode } from './css-node'
 export type { LexerPosition, CommentInfo } from './tokenize'
 
 // Constants - imported from dedicated constants file