Transformer Plugin

Transforms the value seen by a specific validator without modifying the actual input. Other validators on the same field receive the original value.

Options

The options object is a nested map:

{
  [fieldName: string]: {
    [validatorName: string]: (field: string, element: HTMLElement, validator: string) => string
  }
}

Each transform function receives the field name, the DOM element, and the validator name, and returns the value string to use for that validator.

Playground

Notes

• Only the specified validator sees the transformed value — notEmpty on the same field always sees the raw value.
• The transform function is called on every validation run; it does not modify the DOM.
• Disable the plugin with fv.disablePlugin('transformer') to revert to raw values.
• Works with the built-in field-value filter hook added to Core.