Bitovi

validator

A function that validates a value against predefined constraints and returns validation errors, if any are found.

`validator(value)`

function validator( value ) {
  if ( typeof value === "undefined" || value === "" ) {
      return "is required";
  }
}

Parameters

value {*}:
A simple value to validate

Returns

{Error|String|undefined|Array<Error|String>}:

Returns undefined if no errors found. Otherwise, will return an error type with the error message.

Creating a validator

Given that a required validation exists

// Custom required check
const checkRequired = function( val ) {
    if ( typeof value === "undefined" || value === "" ) {
        return false;
    }
    return true;
};

Typically a validator can be created like so

// Validator factory
const makeValidator = function( constraints ) {
    return function( value ) {
        if ( constraints.required && !checkRequired( value ) ) {
            return "is required";
        }
    };
};

Now, creating a validator for any value is possible by doing

const nameValidator = makeValidator( { required: true } );

Which then allows validating values as needed

nameValidator( "Juan" ); //> undefined
nameValidator(); //> 'is required'

Validator Response

The response should match the Errors type. The most flexible response is the Error type which describes the error message any value keys that triggered the error state.