# @swc-node/register > SWC node register Latest version **1.12.1** (published 2026-07-18) · MIT license · 0 weekly downloads ## Install ```sh npm install @swc-node/register pnpm add @swc-node/register yarn add @swc-node/register bun add @swc-node/register ``` ## Health **Score 65/100 (B)** — status: active. Positive: esm support; no vulnerabilities; has provenance; recently updated; high maintenance score. Warnings: low downloads; no types. ## Facts | | | |---|---| | Version | 1.12.1 | | Published | 2026-07-18 | | First published | 2020-07-30 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | none | | Module format | ESM + CommonJS | | Dependencies | 9 | | Unpacked size | 177 KB | | Known vulnerabilities | 0 | | Install scripts | no | | Provenance | attested (GitHub Actions) | | GitHub stars | 1981 | | Author | LongYinan | | Maintainers | broooooklyn | | Keywords | swc, babel, ts-node, napi-rs, uglify, node-rs, napi-rs, napi, n-api, esbuild, tsc, webpack | ## Links - npm: https://www.npmjs.com/package/@swc-node/register - Repository: https://github.com/swc-project/swc-node - Issues: https://github.com/swc-project/swc-node/issues - Funding: https://github.com/sponsors/Brooooooklyn - npm.io page: https://npm.io/package/@swc-node/register ## Dependencies (9) - [debug](https://npm.io/package/debug.md) ^4.4.1 - [tslib](https://npm.io/package/tslib.md) ^2.8.1 - [pirates](https://npm.io/package/pirates.md) ^4.0.7 - [colorette](https://npm.io/package/colorette.md) ^2.0.20 - [oxc-resolver](https://npm.io/package/oxc-resolver.md) ^11.6.1 - [@swc-node/core](https://npm.io/package/@swc-node/core.md) 1.15.0 - [@node-rs/xxhash](https://npm.io/package/@node-rs/xxhash.md) ^1.7.6 - [fast-json-stable-stringify](https://npm.io/package/fast-json-stable-stringify.md) ^2.1.0 - [@swc-node/sourcemap-support](https://npm.io/package/@swc-node/sourcemap-support.md) ^0.6.1 ## Alternatives - [@openai/codex-sdk](https://npm.io/package/@openai/codex-sdk.md) — 731.4K weekly downloads - [babel-plugin-transform-react-jsx](https://npm.io/package/babel-plugin-transform-react-jsx.md) — 565.0K weekly downloads - [babel-helper-remove-or-void](https://npm.io/package/babel-helper-remove-or-void.md) — 508.5K weekly downloads - [@pnpm/store-controller-types](https://npm.io/package/@pnpm/store-controller-types.md) — 186.9K weekly downloads - [react-native-signature-canvas](https://npm.io/package/react-native-signature-canvas.md) — 155.6K weekly downloads ## Recent versions - 1.12.1 (latest) — 2026-07-18 - 1.12.0 — 2026-07-16 - 1.11.1 — 2025-08-17 - 1.10.10 — 2025-03-13 - 1.10.9 — 2024-07-17 - 1.10.8 — 2024-07-16 - 1.10.7 — 2024-07-14 - 1.10.6 — 2024-07-13 - 1.10.5 — 2024-07-13 - 1.10.4 — 2024-07-12 - 1.10.3 — 2024-07-08 - 1.10.2 — 2024-07-05 - 1.10.1 — 2024-07-05 - 1.10.0 — 2024-06-28 - 1.9.2 — 2024-06-08 - … 74 more at https://npm.io/package/@swc-node/register/versions ## README # `@swc-node/register` Downloads > 🚀 Help me to become a full-time open-source developer by [sponsoring me on Github](https://github.com/sponsors/Brooooooklyn) ## Usage ```ts const { register } = require('@swc-node/register/register') register({ ... }) ``` ### CLI ``` node -r @swc-node/register index.ts ``` ### Mocha ``` mocha --require @swc-node/register --watch-extensions ts,tsx "test/**/*.{ts,tsx}" [...args] ``` ### ava ```json // package.json { "ava": { "extensions": ["ts", "tsx"], "require": ["@swc-node/register"], "files": ["packages/**/*.spec.{ts,tsx}"] } } ``` ## Read `tsconfig.json` set `SWC_NODE_PROJECT` or `TS_NODE_PROJECT` env: ```bash SWC_NODE_PROJECT=./tsconfig.test.json mocha --require @swc-node/register --watch-extensions ts,tsx "test/**/*.{ts,tsx}" [...args] ``` `@swc-node/register` respect the following option in `tsconfig`: ### `extends` `@swc-node/register` respect the extends key in `tsconfig.json`, and use the **merged** values. ### `compilerOptions.target` ```ts switch (target) { case ts.ScriptTarget.ES3: return 'es3' case ts.ScriptTarget.ES5: return 'es5' case ts.ScriptTarget.ES2015: return 'es2015' case ts.ScriptTarget.ES2016: return 'es2016' case ts.ScriptTarget.ES2017: return 'es2017' case ts.ScriptTarget.ES2018: return 'es2018' case ts.ScriptTarget.ES2019: return 'es2019' case ts.ScriptTarget.ES2020: case ts.ScriptTarget.ES2021: case ts.ScriptTarget.ES2022: case ts.ScriptTarget.ESNext: case ts.ScriptTarget.Latest: return 'es2020' case ts.ScriptTarget.JSON: return 'es5' } ``` ### `compilerOptions.jsx` If `filename` endsWith `.jsx` or `.tsx`, always set the `jsx: true` in `swc config` regards the `jsx` option in `tsconfig`. If `filename` not endsWith `.jsx` or `.tsx`, set the `jsx: Boolean(tsconfig.compilerOptions.jsx)` in `swc config`. ### compilerOptions.module > notes, if `compilerOptions.module` higher than `es2020`, the `dynamicImport` in `swc config` will be set to `true`. ```ts switch (moduleKind) { case ts.ModuleKind.CommonJS: return 'commonjs' case ts.ModuleKind.UMD: return 'umd' case ts.ModuleKind.AMD: return 'amd' case ts.ModuleKind.ES2015: case ts.ModuleKind.ES2020: case ts.ModuleKind.ESNext: case ts.ModuleKind.None: return 'es6' case ts.ModuleKind.System: throw new TypeError('Do not support system kind module') } ``` ### compilerOptions.experimentalDecorators Respect the boolean value in `tsconfig`. ### compilerOptions.emitDecoratorMetadata Respect the boolean value in `tsconfig`. ### compilerOptions.esModuleInterop Respect the boolean value in `tsconfig`. ### include/exclude `TypeScript` gives files list to `@swc-node/register`, if parse `tsconfig.json` failed or files list empty, `@swc-node/register` will transform all files which were required. And if failed to parse `tsconfig.json`, `@swc-node/register` will print warning which contains failed reason. ## Performance tuning ### Transform cache `@swc-node/register` now keeps a transform cache (memory + disk) keyed by source, filename, compiler options, and runtime versions. Environment variables: - `SWC_NODE_CACHE=0` disable cache. - `SWC_NODE_CACHE_DIR=./path/to/cache` choose disk cache directory. - `SWC_NODE_CACHE_MEMORY_LIMIT=2000` max in-process transform entries. Programmatic cache control: ```js const { clearTransformCache, getTransformCacheDirectory } = require('@swc-node/register/register') // clear memory + disk (default) clearTransformCache() // clear only memory cache clearTransformCache({ memory: true, disk: false }) // inspect resolved disk cache path console.log(getTransformCacheDirectory()) ``` ### Source map memory mode Use `SWC_NODE_SOURCE_MAP_MODE` to tune source map memory behavior: - `auto` (default): inline maps when Node native source maps are enabled, otherwise map-store mode. - `inline`: inline data URL source maps only. - `store`: in-memory map store only (`source-map-support` path). - `both`: inline + store (highest memory use, mainly for compatibility/debug edge cases). - `none`: disable both inline/store map injection. ### Skipping compilation for runtime JS Plain JavaScript files (`.js`, `.mjs`, `.cjs`, `.es`, `.es6`) that Node can already execute are passed through without an SWC transform, which speeds up startup. A file is still transformed when it needs to be — it contains JSX, it uses ESM syntax under CommonJS output, or an `.swcrc` is in effect. Known caveats (kept intentionally, for speed): - A `tsconfig.json` `paths` alias imported via **dynamic** `import('@alias/…')` in a passed-through `.js` file is not rewritten, so the alias will not resolve. Static `import`/`require` are unaffected. Use `.ts`/`.mts` (or a static import) if you rely on alias resolution here. - Dynamically `import()`-ing a CommonJS module from a passed-through `.js` file yields a native module namespace rather than SWC's interop shape (`ns.default` instead of `ns`). --- _Source: https://npm.io/package/@swc-node/register · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._