custom

custom(callback, [ctx])

Effect

Declare a custom restrict by a custom callback function.

Arguments

• callback (Function) - The custom function for restricting. callback has a parameter: the detected value. If validate failed, the callback should throw an error, otherwise, it means validation passed.

• [ctx] (*) - The execution context of callback.

NOTE

Since 1.3.0, callback can return a non-empty string to respect that validating failed, the string means the failure reason. Otherwise, it means validating passed if you return other values.

Example

const schema = racoon.string().custom((val) => {
  if (val.length % 2 === 0) {
    return true;
  }
  throw new Error('The length of detected string should be even');
});
schema.validate('12'); // pass
schema.validate('123'); // fail