SettingControlBase.validate?

Official

Type: (value: V) => string | void | Promise<string | void>

Validate a candidate value before it is persisted. Return a non-empty string to reject the change and surface it as an inline error message below the setting; return void/empty/undefined to accept and persist.

Primarily intended for text-bearing controls (text, textarea, number, file, folder) where the user can enter values the bind's type alone can't constrain.

The stored value may already be invalid when the setting is rendered (e.g. data from a previous version of your plugin). The framework runs validate once on mount and shows the message if the seeded value fails; it does not modify or replace the stored value. Plugins that need to enforce invariants on stored data should validate again when reading their settings.

Since: 1.13.0