##### **Overview of the feature request** `mutateData` types can lead to a simplified developer experience. Following https://github.com/jhipster/generator-jhipster/pull/30369, data mutation can be extracted providing improved composition, simplified experience, better types enforcement. We can improve by providing: - Test support - Derived properties utilities. <!-- Explain the feature request --> ##### **Motivation for or Use Case** <!-- Explain why this new feature is important for you --> ##### **Related issues or PR** <!-- Has a similar feature request been asked for before? Please search both closed & open issues --> - [ ] Checking this box is mandatory (this is just to show you read everything) <!-- Love JHipster? Please consider supporting our collective: 👉 https://opencollective.com/generator-jhipster/donate -->