Custom validation

Add synchronous or asynchronous rules when built-in checks are not enough.

Refinements

Refinements are a way to add custom validation to a schema. You can use the refine() method to add a custom validation function to a schema.

WARNING

Refinement callbacks should return a boolean. Exceptions from application callbacks are not converted into validation issues.

refine()

To add a custom sync validation function to a schema, you can use the refine() method.

final person = object({
  'name': string().min(3),
  'age': number().positive(),
}).refine(onCheck: (value) => value['age'] > 4, error: 'Age is lower than 4', name: 'ageCheck');

refineAsync()

To add a custom async validation function to a schema, you can use the refineAsync() method.

final person = object({
  'name': string().min(3),
  'age': number().positive(),
}).refineAsync(onCheck: (value) async => value['age'] > 4, error: 'Age is lower than 4', name: 'ageCheck');

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