> For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt.

# CompactHashedModuleIdsPlugin


[Added in v2.2.1](https://github.com/web-infra-dev/rspack/releases/tag/v2.2.1)Rspack only

`CompactHashedModuleIdsPlugin` hashes module identifiers and assigns the shortest available prefix of each encoded hash. Compared with `deterministic`, it produces more compact ids that preserve stability while reducing bundle size and improving runtime indexing performance. The first character uses `a-zA-Z`, and subsequent characters use `a-zA-Z0-9`. An id is extended only when its shorter prefix is already used.

:::warning Deprecated alias
`CompatHashedModuleIdsPlugin` was available in Rspack 2.2.0. It is deprecated and was renamed to `CompactHashedModuleIdsPlugin` in Rspack 2.2.1. The old name remains available as a compatibility alias.
:::

:::warning
The generated module ids are case-sensitive and may contain uppercase letters. On case-insensitive file systems, avoid using `[id]` as the only distinguishing placeholder in [Asset module filenames](/config/output.md#outputassetmodulefilename) or [WebAssembly module filenames](/config/output.md#outputwebassemblymodulefilename). Prefer `[contenthash]`, or include it alongside `[id]`.
:::

[`optimization.moduleIds: 'compact-hashed'`](/config/optimization.md#optimizationmoduleids) uses this plugin internally. Use the plugin directly when you need to customize the minimum encoded id length.

## Examples

```js title="rspack.config.mjs"
import rspack from '@rspack/core';

export default {
  optimization: {
    moduleIds: false,
  },
  plugins: [
    new rspack.ids.CompactHashedModuleIdsPlugin({
      minLength: 1,
    }),
  ],
};
```

## Options

### minLength

- **Type:** `number`
- **Default:** `1`
- **Range:** Integer from `1` to `11`

The minimum encoded id length. Rspack extends an id one character at a time when its hash prefix is already used. Increasing `minLength` expands the initial id space, reducing prefix collisions and making generated output and caching more stable. The tradeoff is that module ids become longer.