[PROPOSAL] Custom validation message formatter

[sendyhalim]

There are needs where we want to format validation message parameters, for example: I'm validating a salary input with minValue.

Current behaviour:

const rules = {
  salary: ['minValue:1000000']
};

const input = {
  salary: 999999
};

satpam.validate(rules, input); // "Salary must be greater than or equal to 1000000."

The salary validation message is "Salary must be greater than or equal to 1000000.", notice the 1000000, the ideal situation is to have some kind of parameter formatter so we can customise the rendering of validation parameters .

Desired behaviour:

const locale = 'id';

const rules = {
  salary: ['minValue:1000000']
};

const input = {
  salary: 999999
};

const options = {
  // The formatter will be run before passing validation message
  // parameters into template string.
  // https://github.com/cermati/satpam/blob/master/src/validators/min-value.js#L18
  validationMessageParamsFormatter: ({ propertyName, propertyValue, inputObj, violatedRule }) => {
    // For simplicity's sake, we're going to only use `minValue` rule, it has 1 param.
    const formattedParam  = currencyFormatter.format(violatedRule.params[0]); 
  
    return {
      propertyName: propertyNameByLocale[locale], // You can also do translation here
      ruleParams: [formattedParam]
    };
  },


   // The formatted validation message parameters will be feed into template string which 
   // could have further customisation https://github.com/cermati/satpam/issues/103
  validationMessagePack: ....
}

satpam.validate(rules, input, options); // "Pendapatan harus lebih besar dari IDR 1.000.000."

[sendyhalim]

Development done 🏖️