# `@swc-node/register`

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## 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.