# OutputFormat

Output format for the generated JavaScript files.

- Source: [`aws-lambda-nodejs/lib/types.ts`](https://github.com/aws/aws-cdk/blob/v2.274.0/packages/aws-cdk-lib/aws-lambda-nodejs/lib/types.ts#L324)
- Type last changed: v2.7.0 · 12 Jan 2022

## Example

```ts
new nodejs.NodejsFunction(this, 'my-handler', {
  bundling: {
    minify: true, // minify code, defaults to false
    sourceMap: true, // include source map, defaults to false
    sourceMapMode: nodejs.SourceMapMode.INLINE, // defaults to SourceMapMode.DEFAULT
    sourcesContent: false, // do not include original source into source map, defaults to true
    target: 'es2020', // target environment for the generated JavaScript code
    loader: { // Use the 'dataurl' loader for '.png' files
      '.png': 'dataurl',
    },
    define: { // Replace strings during build time
      'process.env.API_KEY': JSON.stringify('xxx-xxxx-xxx'),
      'process.env.PRODUCTION': JSON.stringify(true),
      'process.env.NUMBER': JSON.stringify(123),
    },
    logLevel: nodejs.LogLevel.ERROR, // defaults to LogLevel.WARNING
    keepNames: true, // defaults to false
    tsconfig: 'custom-tsconfig.json', // use custom-tsconfig.json instead of default,
    metafile: true, // include meta file, defaults to false
    banner: '/* comments */', // requires esbuild >= 0.9.0, defaults to none
    footer: '/* comments */', // requires esbuild >= 0.9.0, defaults to none
    charset: nodejs.Charset.UTF8, // do not escape non-ASCII characters, defaults to Charset.ASCII
    format: nodejs.OutputFormat.ESM, // ECMAScript module output format, defaults to OutputFormat.CJS (OutputFormat.ESM requires Node.js >= 14)
    mainFields: ['module', 'main'], // prefer ECMAScript versions of dependencies
    inject: ['./my-shim.js', './other-shim.js'], // allows to automatically replace a global variable with an import from another file
    esbuildArgs: { // Pass additional arguments to esbuild
      "--log-limit": "0",
      "--splitting": true,
    },
  },
});
```

## Members

| Member | Description |
| --- | --- |
| `CJS` | CommonJS. |
| `ESM` | ECMAScript module. |

## Referenced by

- [`BundlingOptions`](/v2/docs/aws-cdk-lib.aws_lambda_nodejs.BundlingOptions).format