Enhance Joi Error Messages for User-Friendliness with Optional `{ format: true }` Feature

[pavan-dulam]

Runtime

Node.js

Runtime version

Node.js 22 (LTS)

Module version

Joi v17.x

Used with

Standalone and Express.js applications

Any other relevant information

• Developers currently have to manually override or wrap Joi's default error messages to create user-friendly feedback.
• The technical error messages not only clutter the UI but may also inadvertently leak sensitive validation details.
• Examples of current error messages:
  • `"password" with value "pass" fails to match the required pattern: /^[a-zA-Z0-9]{8,30}$/`
  • `"mixedField" must be one of [string, number]`
  • `"settings.notifications" is required`
  • `"tree.child.child.child.name" is required`

What problem are you trying to solve?

What problem are you trying to solve?

• User Experience: End users see cryptic and technical messages that are hard to understand, leading to a poor overall user experience.
• Developer Overhead: Developers are forced to write custom error-handling logic for every field and scenario, increasing both development time and potential for inconsistency.
• Security Concerns: Technical error messages may expose underlying validation logic or sensitive details that should remain internal.
• Maintainability: A built-in, standardized approach to formatting error messages would reduce redundancy and improve code clarity across projects.

Do you have a new or modified API suggestion to solve the problem?

• Feature Request: Introduce an optional parameter { format: true } in the Joi validation options.

  • Behavior when enabled:
    • Simplify messages: Strip out technical details and present clear, concise messages that can be safely shown directly to end users.
    • Consistency: Automatically apply friendly formatting for all types of validation errors (e.g., pattern mismatches, required fields, type errors).
  • Example transformation:

    • Before: `"password" with value "pass" fails to match the required pattern: /^[a-zA-Z0-9]{8,30}$/`

    • After: `Password must be 8-30 characters long and contain only letters and numbers.`

    • Before:`"mixedField" must be one of [string, number]`

    • After:"Mixed Field must be either a text or a number."

    • Before: `"settings.notifications" is required`

    • After:"Notification settings are required."

    • Before: `"tree.child.child.child.name" is required`

    • After: "Name is required."

• Impact:

  • Enhanced UX: Streamlined error messages would lead to a better front-end experience.
  • Reduced Developer Hassle: Eliminates the need for repetitive custom error message coding, allowing developers to focus on core functionality.
  • Security Improvement: Minimizes exposure of internal validation patterns and logic.

I am ready to contribute a PR to implement this feature and collaborate on refining the approach. Looking forward to your feedback!

[pavan-dulam]

@Marsup I am ready to contribute a PR to implement this feature and collaborate on refining the approach. Looking forward to your feedback!