#CompatHashedModuleIdsPlugin

CompatHashedModuleIdsPlugin 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.

optimization.moduleIds: 'compat-hashed' uses this plugin internally. Use the plugin directly when you need to customize the minimum encoded id length.

import rspack from '@rspack/core';

export default {
  optimization: {
    moduleIds: false,
  },
  plugins: [
    new rspack.ids.CompatHashedModuleIdsPlugin({
      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.