fix: avoid importing unused param parsers

Author: posva

packages/router/src/unplugin/codegen/generateParamParsers.spec.ts

@@ -2,6 +2,7 @@ import { describe, expect, it, test } from 'vitest'
 import {
   warnMissingParamParsers,
   collectMissingParamParsers,
+  collectUsedParamParserNames,
   generateParamParsersTypesDeclarations,
   generateParamsTypes,
   generateParamParserOptions,
@@ -158,6 +159,49 @@ describe('collectMissingParamParsers', () => {
   })
 })
 
+describe('collectUsedParamParserNames', () => {
+  it('returns an empty set when no route references a parser', () => {
+    const tree = new PrefixTree(DEFAULT_OPTIONS)
+    tree.insert('users', 'users.vue')
+    tree.insert('posts/[id]', 'posts/[id].vue')
+
+    expect(collectUsedParamParserNames(tree).size).toBe(0)
+  })
+
+  it('collects parser names from path params', () => {
+    const tree = new PrefixTree(DEFAULT_OPTIONS)
+    tree.insert('users/[id=uuid]', 'users/[id=uuid].vue')
+    tree.insert('posts/[slug=slug]', 'posts/[slug=slug].vue')
+
+    expect(collectUsedParamParserNames(tree)).toEqual(new Set(['uuid', 'slug']))
+  })
+
+  it('includes native parser names', () => {
+    const tree = new PrefixTree(DEFAULT_OPTIONS)
+    tree.insert('users/[id=int]', 'users/[id=int].vue')
+
+    expect(collectUsedParamParserNames(tree)).toEqual(new Set(['int']))
+  })
+
+  it('collects parser names from query params', () => {
+    const tree = new PrefixTree(DEFAULT_OPTIONS)
+    const node = tree.insert('search', 'search.vue')
+    node.setCustomRouteBlock('search.vue', {
+      params: { query: { id: 'uuid' } },
+    })
+
+    expect(collectUsedParamParserNames(tree)).toEqual(new Set(['uuid']))
+  })
+
+  it('deduplicates parsers referenced multiple times', () => {
+    const tree = new PrefixTree(DEFAULT_OPTIONS)
+    tree.insert('users/[id=uuid]', 'users/[id=uuid].vue')
+    tree.insert('teams/[id=uuid]', 'teams/[id=uuid].vue')
+
+    expect(collectUsedParamParserNames(tree)).toEqual(new Set(['uuid']))
+  })
+})
+
 describe('generateParamParsersTypesDeclarations', () => {
   it('returns empty string for empty param parsers map', () => {
     const paramParsers: ParamParsersMap = new Map()

packages/router/src/unplugin/codegen/generateParamParsers.ts

@@ -66,6 +66,24 @@ export interface MissingParamParser {
   filePaths: string[]
 }
 
+/**
+ * Walks the route tree and returns the set of parser names referenced by any
+ * path or query param. Native parser names (`int`, `bool`) and references to
+ * parsers not present on disk are included as-is — callers decide what to do
+ * with them.
+ */
+export function collectUsedParamParserNames(tree: PrefixTree): Set<string> {
+  const used = new Set<string>()
+  for (const node of tree.getChildrenDeepSorted()) {
+    for (const param of node.params) {
+      if (param.parser) {
+        used.add(param.parser)
+      }
+    }
+  }
+  return used
+}
+
 export function collectMissingParamParsers(
   tree: PrefixTree,
   paramParsers: ParamParsersMap

packages/router/src/unplugin/codegen/generateRouteResolver.spec.ts

@@ -1404,4 +1404,97 @@ describe('generateRouteResolver', () => {
       expect(warnings).not.toContain('"/members"')
     })
   })
+
+  describe('param parser filtering', () => {
+    type ParamParserEntry = NonNullable<ReturnType<ParamParsersMap['get']>>
+    const uuidEntry = {
+      name: 'uuid',
+      typeName: 'Param_uuid',
+      relativePath: 'parsers/uuid',
+      absolutePath: '/abs/parsers/uuid',
+    } satisfies ParamParserEntry
+    const slugEntry = {
+      name: 'slug',
+      typeName: 'Param_slug',
+      relativePath: 'parsers/slug',
+      absolutePath: '/abs/parsers/slug',
+    } satisfies ParamParserEntry
+
+    it('omits imports and normalized declarations for unused parsers', () => {
+      const tree = new PrefixTree(DEFAULT_OPTIONS)
+      tree.insert('users/[id=uuid]', 'users/[id=uuid].vue')
+
+      const importsMap = new ImportsMap()
+      const paramParsersMap: ParamParsersMap = new Map([
+        ['uuid', uuidEntry],
+        ['slug', slugEntry],
+      ])
+
+      const resolver = generateRouteResolver(
+        tree,
+        DEFAULT_OPTIONS,
+        importsMap,
+        paramParsersMap
+      )
+
+      expect(resolver).toContain('_normalized_PARAM_PARSER__uuid')
+      expect(resolver).not.toContain('PARAM_PARSER__slug')
+      expect(resolver).not.toContain('_normalized_PARAM_PARSER__slug')
+
+      const imports = importsMap.toString()
+      expect(imports).toContain("from '/abs/parsers/uuid'")
+      expect(imports).not.toContain("from '/abs/parsers/slug'")
+    })
+
+    it('omits all parser imports when no route references any parser', () => {
+      const tree = new PrefixTree(DEFAULT_OPTIONS)
+      tree.insert('users/[id]', 'users/[id].vue')
+
+      const importsMap = new ImportsMap()
+      const paramParsersMap: ParamParsersMap = new Map([
+        ['uuid', uuidEntry],
+        ['slug', slugEntry],
+      ])
+
+      const resolver = generateRouteResolver(
+        tree,
+        DEFAULT_OPTIONS,
+        importsMap,
+        paramParsersMap
+      )
+
+      expect(resolver).not.toContain('_normalizeParamParser')
+      expect(resolver).not.toContain('PARAM_PARSER__uuid')
+      expect(resolver).not.toContain('PARAM_PARSER__slug')
+
+      const imports = importsMap.toString()
+      expect(imports).not.toContain('_normalizeParamParser')
+      expect(imports).not.toContain("from '/abs/parsers/uuid'")
+      expect(imports).not.toContain("from '/abs/parsers/slug'")
+    })
+
+    it('detects parsers referenced from query params', () => {
+      const tree = new PrefixTree(DEFAULT_OPTIONS)
+      const node = tree.insert('search', 'search.vue')
+      node.setCustomRouteBlock('search.vue', {
+        params: { query: { id: 'uuid' } },
+      })
+
+      const importsMap = new ImportsMap()
+      const paramParsersMap: ParamParsersMap = new Map([
+        ['uuid', uuidEntry],
+        ['slug', slugEntry],
+      ])
+
+      const resolver = generateRouteResolver(
+        tree,
+        DEFAULT_OPTIONS,
+        importsMap,
+        paramParsersMap
+      )
+
+      expect(resolver).toContain('_normalized_PARAM_PARSER__uuid')
+      expect(resolver).not.toContain('_normalized_PARAM_PARSER__slug')
+    })
+  })
 })

packages/router/src/unplugin/codegen/generateRouteResolver.ts

@@ -8,6 +8,7 @@ import {
   generatePathParamsOptions,
   generateParamParserOptions,
   generateNormalizedParamParsersDeclarations,
+  collectUsedParamParserNames,
 } from './generateParamParsers'
 import { generatePageImport, formatMeta } from './generateRouteRecords'
 
@@ -78,6 +79,13 @@ export function generateRouteResolver(
   importsMap: ImportsMap,
   paramParsersMap: ParamParsersMap
 ): string {
+  // restrict imports + normalized declarations to parsers actually referenced
+  // by a route, so unused parser files don't get pulled into the bundle
+  const usedParserNames = collectUsedParamParserNames(tree)
+  const usedParamParsersMap: ParamParsersMap = new Map(
+    Array.from(paramParsersMap).filter(([key]) => usedParserNames.has(key))
+  )
+
   const state: GenerateRouteResolverState = { id: 0, matchableRecords: [] }
   const records = tree.getChildrenSorted().map(node =>
     generateRouteRecord({
@@ -87,7 +95,7 @@ export function generateRouteResolver(
       state,
       options,
       importsMap,
-      paramParsersMap,
+      paramParsersMap: usedParamParsersMap,
     })
   )
 
@@ -97,7 +105,7 @@ export function generateRouteResolver(
   importsMap.add('vue-router/experimental', 'normalizeRouteRecord')
 
   const normalizedDeclarations = generateNormalizedParamParsersDeclarations(
-    paramParsersMap,
+    usedParamParsersMap,
     importsMap
   )