cleanDir

• Type: boolean
• Default: false
• Path: output.cleanDir

Clean the output directory (output.dir) before emitting output.

Examples

Basic usage

export default {
  output: {
    cleanDir: true,
  },
};

Multiple outputs in one config

When multiple outputs share the same directory, only set cleanDir: true for the first output:

export default {
  output: [
    {
      dir: 'dist',
      format: 'es',
      cleanDir: true, // Clean on first output
    },
    {
      dir: 'dist',
      format: 'cjs',
      // cleanDir defaults to false, so files from first output are preserved
    },
  ],
};

Multiple configurations

When multiple configurations share the same directory, only set cleanDir: true for the first configuration:

export default [
  {
    input: 'src/index.js',
    output: {
      dir: 'dist',
      cleanDir: true, // Clean on first configuration
    },
  },
  {
    input: 'src/other.js',
    output: {
      dir: 'dist',
      // cleanDir defaults to false, so files from first config are preserved
    },
  },
];

Different directories in multiple outputs

When multiple outputs use different directories, you can safely use cleanDir: true for each:

export default {
  output: [
    {
      dir: 'dist/es',
      format: 'es',
      cleanDir: true, // Safe - different directory
    },
    {
      dir: 'dist/cjs',
      format: 'cjs',
      cleanDir: true, // Safe - different directory
    },
  ],
};

In-depth

Execution timing

The timing of the directory cleanup is important for plugin compatibility:

• The cleanup occurs before the generateBundle hook is called
• Files created by plugins during generateBundle or writeBundle hooks are not deleted
• This ensures that plugin-generated files are preserved even when cleanDir is enabled

For advanced use cases involving multiple outputs with the same output.dir, consider using a separate cleanup script for more control over the cleanup process.

⚠️ Multiple configurations behavior

When using multiple configurations or outputs, the cleanDir option will be executed separately for each configuration/output following the order they are defined.

The two patterns:

• Multiple configurations: export default defineConfig([{ output: { cleanDir: true, ... } }, { output: {...} }])
• Multiple outputs in one config: defineConfig({ output: [{ cleanDir: true, ... }, { ... }] })

The problem:

If multiple outputs share the same output.dir and have cleanDir: true, later outputs may clean files generated by earlier outputs. This happens because each output executes its cleanup independently.

Best practice:

To avoid this issue, only set cleanDir: true for the first output, or use different output directories. This ensures that all generated files are preserved.