refactor: Colocate stop node workaround with TODO for revert

Author: macieklamberski

src/common/config.ts

@@ -179,17 +179,6 @@ export const namespacePrefixes = Object.entries(namespaceUris).reduce(
   {} as Record<string, string>,
 )
 
-// Namespace elements that act as containers for other namespace elements.
-// Used during stop node expansion to generate paths through these containers.
-export const namespaceContainers = [
-  'media:group',
-  'media:content',
-  'media:group.media:content',
-  'media:embed',
-  'podcast:liveitem',
-  'itunes:owner',
-]
-
 export const namespaceStopNodes = [
   ...acastStopNodes,
   ...adminStopNodes,

src/common/utils.ts

@@ -1,6 +1,5 @@
 import { decodeHTML } from 'entities'
 import type { XMLBuilder } from 'fast-xml-parser'
-import { Expression } from 'path-expression-matcher'
 import type {
   AnyOf,
   DateLike,
@@ -912,22 +911,32 @@ export const parseJsonObject = (value: unknown): unknown => {
   } catch {}
 }
 
+// TODO: Remove expandStopNodes and namespaceContainers after fast-xml-parser
+// resolves stop node performance regression. Revert feed configs from
+// ...expandStopNodes(namespaceStopNodes, [...]) back to ...namespaceStopNodes.
+// https://github.com/NaturalIntelligence/fast-xml-parser/issues/816
+
+// Namespace elements that act as containers for other namespace elements.
+const namespaceContainers = [
+  'media:group',
+  'media:content',
+  'media:group.media:content',
+  'media:embed',
+  'podcast:liveitem',
+  'itunes:owner',
+]
+
 // Expands wildcard stop nodes (*.prefix:element) into explicit paths for
 // each feed container, including paths through namespace containers (e.g.
 // media:group, podcast:liveitem). Only crosses containers with leaves from
-// the same namespace prefix. Pre-constructs Expression objects once at
-// module load to avoid re-parsing on every XMLParser.parse() call.
-// When fxp resolves its performance regression, this can be replaced with
-// raw wildcard strings passed directly to XMLParser.
-export const createStopNodeExpressions = (
-  wildcardStopNodes: Array<string>,
-  explicitStopNodes: Array<string>,
+// the same namespace prefix.
+export const expandStopNodes = (
+  stopNodes: Array<string>,
   feedContainerPaths: Array<string>,
-  namespaceContainers: Array<string>,
-): Array<Expression> => {
+): Array<string> => {
   const set = new Set<string>()
 
-  for (const node of wildcardStopNodes) {
+  for (const node of stopNodes) {
     const suffix = node.slice(2)
     const prefix = suffix.split(':')[0]
 
@@ -942,9 +951,5 @@ export const createStopNodeExpressions = (
     }
   }
 
-  for (const node of explicitStopNodes) {
-    set.add(node)
-  }
-
-  return [...set].map((node) => new Expression(node))
+  return [...set]
 }

src/feeds/atom/parse/config.ts

@@ -1,14 +1,15 @@
 import { XMLParser } from 'fast-xml-parser'
+import { Expression } from 'path-expression-matcher'
 import {
-  namespaceContainers,
   namespacePrefixes,
   namespaceStopNodes,
   namespaceUris,
   parserConfig,
 } from '../../../common/config.js'
-import { createNamespaceNormalizator, createStopNodeExpressions } from '../../../common/utils.js'
+import { createNamespaceNormalizator, expandStopNodes } from '../../../common/utils.js'
 
-const feedStopNodes = [
+export const stopNodes = [
+  ...expandStopNodes(namespaceStopNodes, ['feed', 'feed.entry', 'feed.entry.source']),
   'feed.author.name',
   'feed.author.uri',
   'feed.author.url', // Atom 0.3.
@@ -70,16 +71,9 @@ const feedStopNodes = [
   'feed.entry.modified', // Atom 0.3.
 ]
 
-const stopNodeExpressions = createStopNodeExpressions(
-  namespaceStopNodes,
-  feedStopNodes,
-  ['feed', 'feed.entry', 'feed.entry.source'],
-  namespaceContainers,
-)
-
 export const parser = new XMLParser({
   ...parserConfig,
-  stopNodes: stopNodeExpressions,
+  stopNodes: stopNodes.map((node) => new Expression(node)),
 })
 
 export const normalizeNamespaces = createNamespaceNormalizator(namespaceUris, namespacePrefixes, [

src/feeds/rdf/parse/config.ts

@@ -1,14 +1,20 @@
 import { XMLParser } from 'fast-xml-parser'
+import { Expression } from 'path-expression-matcher'
 import {
-  namespaceContainers,
   namespacePrefixes,
   namespaceStopNodes,
   namespaceUris,
   parserConfig,
 } from '../../../common/config.js'
-import { createNamespaceNormalizator, createStopNodeExpressions } from '../../../common/utils.js'
+import { createNamespaceNormalizator, expandStopNodes } from '../../../common/utils.js'
 
-const feedStopNodes = [
+export const stopNodes = [
+  ...expandStopNodes(namespaceStopNodes, [
+    'rdf:rdf.channel',
+    'rdf:rdf.item',
+    'rdf:rdf.image',
+    'rdf:rdf.textinput',
+  ]),
   'rdf:rdf.channel.title',
   'rdf:rdf.channel.link',
   'rdf:rdf.channel.description',
@@ -24,16 +30,9 @@ const feedStopNodes = [
   'rdf:rdf.textinput.link',
 ]
 
-const stopNodeExpressions = createStopNodeExpressions(
-  namespaceStopNodes,
-  feedStopNodes,
-  ['rdf:rdf.channel', 'rdf:rdf.item', 'rdf:rdf.image', 'rdf:rdf.textinput'],
-  namespaceContainers,
-)
-
 export const parser = new XMLParser({
   ...parserConfig,
-  stopNodes: stopNodeExpressions,
+  stopNodes: stopNodes.map((node) => new Expression(node)),
 })
 
 export const normalizeNamespaces = createNamespaceNormalizator(namespaceUris, namespacePrefixes, [

src/feeds/rss/parse/config.ts

@@ -1,12 +1,12 @@
 import { XMLParser } from 'fast-xml-parser'
+import { Expression } from 'path-expression-matcher'
 import {
-  namespaceContainers,
   namespacePrefixes,
   namespaceStopNodes,
   namespaceUris,
   parserConfig,
 } from '../../../common/config.js'
-import { createNamespaceNormalizator, createStopNodeExpressions } from '../../../common/utils.js'
+import { createNamespaceNormalizator, expandStopNodes } from '../../../common/utils.js'
 
 // These elements can appear both inside <channel> and as direct children of
 // <rss> in malformed feeds, so stop nodes are generated for both paths.
@@ -35,7 +35,8 @@ const sharedStopNodes = [
   'item.source',
 ]
 
-const feedStopNodes = [
+export const stopNodes = [
+  ...expandStopNodes(namespaceStopNodes, ['rss.channel', 'rss.channel.item', 'rss', 'rss.item']),
   'rss.channel.title',
   'rss.channel.link',
   'rss.channel.description',
@@ -57,16 +58,9 @@ const feedStopNodes = [
   ...sharedStopNodes.map((node) => `rss.${node}`),
 ]
 
-const stopNodeExpressions = createStopNodeExpressions(
-  namespaceStopNodes,
-  feedStopNodes,
-  ['rss.channel', 'rss.channel.item', 'rss', 'rss.item'],
-  namespaceContainers,
-)
-
 export const parser = new XMLParser({
   ...parserConfig,
-  stopNodes: stopNodeExpressions,
+  stopNodes: stopNodes.map((node) => new Expression(node)),
 })
 
 export const normalizeNamespaces = createNamespaceNormalizator(namespaceUris, namespacePrefixes)

src/opml/parse/config.ts

@@ -23,11 +23,7 @@ export const stopNodes = [
   // '*.outline.outline',
 ]
 
-// Pre-construct Expression objects once at module load to avoid re-parsing
-// stop node strings on every XMLParser.parse() call.
-const stopNodeExpressions = stopNodes.map((node) => new Expression(node))
-
 export const parser = new XMLParser({
   ...parserConfig,
-  stopNodes: stopNodeExpressions,
+  stopNodes: stopNodes.map((node) => new Expression(node)),
 })