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perf: use native magic-string #771

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perf: use native magic-string #771

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3 changes: 2 additions & 1 deletion package.json
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Original file line number Diff line number Diff line change
Expand Up @@ -162,6 +162,7 @@
"muggle-string": "^0.4.1",
"pathe": "^2.0.3",
"picomatch": "^4.0.3",
"rolldown-string": "^0.2.1",
"scule": "^1.3.0",
"tinyglobby": "^0.2.15",
"unplugin": "^2.3.11",
Expand Down Expand Up @@ -206,7 +207,7 @@
"rollup": "^4.53.3",
"semver": "^7.7.3",
"ts-expect": "^1.3.0",
"tsdown": "0.17.4",
"tsdown": "0.18.0",
"typescript": "^5.9.3",
"unplugin-auto-import": "^20.3.0",
"unplugin-vue-markdown": "^29.2.0",
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21 changes: 16 additions & 5 deletions pnpm-lock.yaml
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14 changes: 4 additions & 10 deletions src/data-loaders/auto-exports.ts
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
import { createFilter } from 'unplugin-utils'
import type { Plugin } from 'vite'
import MagicString from 'magic-string'
import { withMagicString } from 'rolldown-string'
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⚠️ Potential issue | 🔴 Critical

🧩 Analysis chain

🏁 Script executed:

cat -n src/data-loaders/auto-exports.ts | sed -n '1,10p'

Repository: posva/unplugin-vue-router

Length of output: 520

🏁 Script executed:

cat -n src/data-loaders/auto-exports.ts | sed -n '75,95p'

Repository: posva/unplugin-vue-router

Length of output: 708

🌐 Web query:

rolldown-string withMagicString API

💡 Result:

Short answer: there’s no widely used package named "rolldown-string". If you want the behavior (convert text files to modules) in Rolldown, implement a small plugin that uses MagicString — same pattern Rollup plugins use (transform/renderChunk returning code + sourcemap via MagicString). See MagicString docs and examples of Rollup plugins that do this.

Minimal example (conceptual):

  • import MagicString from 'magic-string'
  • in plugin transform(id, code) for matching files:
    • const s = new MagicString(code)
    • s.prepend("export default ")
    • s.append(";")
    • return { code: s.toString(), map: s.generateMap({ hires: true }) }

References:

  • MagicString (API & usage). [1]
  • Rolldown package/homepage (use same plugin hooks as Rollup). [2]
  • Example Rollup plugins using MagicString (pattern you can copy). [3]

Sources:
[1] Rich Harris — magic-string (GitHub README).
[2] rolldown package / homepage (npm).
[3] Example Rollup plugin code using MagicString (e.g., preserve-shebang / renderChunk).

rolldown-string package not found in standard documentation.

The withMagicString API from rolldown-string cannot be verified—this package does not appear in npm or standard documentation. The standard pattern for Rollup/Rolldown plugins requires explicit return of { code: s.toString(), map: s.generateMap({...}) }, not relying on automatic return value management. Either this is a custom/internal package that requires documentation, or the import path is incorrect.

🤖 Prompt for AI Agents 
In src/data-loaders/auto-exports.ts around line 3, the import of withMagicString
from 'rolldown-string' is invalid/unpublished and the transform must explicitly
return { code, map }; replace the unknown import with a known approach (e.g.,
import MagicString from 'magic-string' or the correct helper package),
instantiate a MagicString for your source edits, and ensure the plugin/transform
returns an object like { code: s.toString(), map: s.generateMap({ hires: true })
}; if you intended a custom helper, add/update that module and document it and
ensure package.json includes the correct dependency.

import { findStaticImports, parseStaticImport } from 'mlly'
import { resolve } from 'pathe'
import { StringFilter, type UnpluginOptions } from 'unplugin'
Expand Down Expand Up @@ -79,21 +79,15 @@ export function AutoExportLoaders({
id: transformFilter,
},

handler(code) {
handler: withMagicString((s) => {
const code = s.toString()
const loadersToExports = extractLoadersToExport(code, filterPaths, root)

if (loadersToExports.length <= 0) return

const s = new MagicString(code)
s.append(
`\nexport const __loaders = [\n${loadersToExports.join(',\n')}\n];\n`
)

return {
code: s.toString(),
map: s.generateMap(),
}
},
}),
},
}
}
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4 changes: 2 additions & 2 deletions tsdown.config.ts
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
import { defineConfig, type Options } from 'tsdown'
import { defineConfig, type UserConfig } from 'tsdown'

export const commonOptions = {
format: ['cjs', 'esm'],
Expand All @@ -10,7 +10,7 @@ export const commonOptions = {
'@pinia/colada',
'pinia',
],
} satisfies Options
} satisfies UserConfig

export default defineConfig([
{
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