Custom Normalizers

Basic usage

Here is an example of registering a Normalizer called "example".

Register custom normalizer

Registering Normalizer uses the registerNormalizer() method.

Validator.registerNormalizer('example', (value, params, previousValue, values, previousValues) => {
  return parseInt(value, 10);
});

registerNormalizer() has the following structure.

registerNormalizer(name: string, normalizer: Normalizer, options: BuiltinNormalizerOptions = {}): void

Normalizer has the following structure. It takes the same arguments as Inline normalizer.

(value: any, params: NormalizeParams, previousValue: any, values: Values, previousValues: Values): any;

BuiltinNormalizerOptions is an object with the following structure.

{
  depends?: NormalizerDepends;
  override?: boolean;
}

Custom normalizer usage

Registered normalizers can be used like any other normalizer.

const v = new Validator(data, rules, {
  normalizers: {
    fieldName: {
      // Registered your normalizers
      example: true,
    },
  },
});

Advanced usage

Passing parameters

Let's pass parameters so that we can adjust the radix of "example" earlier.

{
  normalizers: {
    fieldName: {
      example: { radix: 16 }
    }
  }
}

Pass the parameters to params.

Validator.registerNormalizer('example', (value, params, previousValue, values, previousValues) => {
  return parseInt(value, params.radix || 10);
});

Dependence on other normalizers

As with custom rules it is possible to dependence on other Normalizers.

In the following example, whitespace removed values are passed.

Validator.registerNormalizer('example', (value, params, previousValue, values, previousValues) => {
  return parseInt(value, params.radix || 10);
}, {
  depends: { trim: true },
});

Override builtin normalizers

You may want to override the normalizers provided by drip-form-validator.
In such a case the override option is useful.

Validator.registerNormalizer('toString', (value, params, previousValue, values, previousValues) => {
  /* override normalizer specification */
}, {
  override: true,
});

An error will occur if you normally try to register a normalizer with the same name.
You can override built-in normalizers by enabling override option.

Written test for Custom normalizers

TODO