README.md

js-validation-tool

Uses validator.js under the hood.

Installation and usage

Install the library with npm i js-validation-tool

Import

const jsValidator = require('js-validator-tool');
// or
const validate = require('js-validator-tool/core/validate');
const validations = require('js-validator-tool/core/validations);
// or
const { validate, validateModel, validations } = require('js-validator-tool);

Validation models

Models are functions that returns an object, each property has a collection of validations.

const ModelValidations = require('js-validator-tool/core/modelValidations');
const userModel = () => ({
  name: [ModelValidations.string.isNotEmpty()],
  age: [ModelValidations.number.isBetween({ from: 18, to: 30 })],
  isNew: [ModelValidations.boolean.isBool()]
});

Single validations

Every validation takes the following parameters

Parameter	Description	Optional
key	Property name being validated	No
value	Value to validate	No
configuration	Validation additional parameters	Yes
errorMessage	Custom error message when validation is failed	Yes

returns a Promise<{ fields: [String], isValid: Boolean }>

Available validations

Validations are separated in types (string, boolean, number and common)

String validations

Validation	Description	Params
isNotEmpty	Returns true if the given string value is not empty
isString	Returns true if the given value is a string
isMongoId	Returns true if the given value is a valid mongo id
isDate	Returns true if the given value is a date
isEmail	Returns true if the given value is a valid email address
isLength	Returns true if the given string matches the provided min - max length	{min: number, max: number}

Common validations

Validation	Description
isOptional	Set the property as optional to be validated
isOneOf	Returns true when any value matches the provided array

Number validations

Validation	Description
isNumeric	Returns true when the given value is a valid number
isNotZero	Returns true when the provided value is different to 0
isBetween	Returns true when the provided value matches with the provided range (config)

Bool validations

Validation	Description
isBool	Returns true if the given value is boolean ('true' is valid)

Example

const validationResult = await validate([
  validations.string.isString('name', 'Jhon'),
  validations.number.isNotZero('age', 0),
]);
console.log(validationResult); // prints: { isValid: true, fields: ["Field 'age', expected not to be Zero. Got 0"] }

Add your own validations

const customValidator = (prop, value) => {
  const onFailureMessage = `Field '${prop}', is not valid`;
  return {
    validation: 'myCustomValidation', // validation name
    property: prop,
    onFailureMessage,
    execute: () => value !== undefined,
  };
};

const customValResult = await validate([customValidator('name', undefined)]);
console.log(customValResult); // prints { isValid: false, fields: [ "Field 'name', is not valid" ] }

Full example

const { validate, validateModel, validations, modelValidations } = require('js-validator-tool');

(async () => {
  // model validator example
  const productModel = () => ({
    name: [modelValidations.string.isNotEmpty('name', entity.name)],
    description: [
      modelValidations.common.isOptional('description', entity.description),
      modelValidations.string.isNotEmpty('description', entity.description),
    ],
    isNew: [modelValidations.boolean.isBool('isNew', entity.isNew)],
  });

  const product = {
    name: 'Super box',
    // description is marked as optional, so can be omitted
    isNew: false,
  };

  const modelValidationResult = await validateModel(productModel, product);
  console.log(modelValidationResult); // prints {isValid: true, fields: []}

  // single validations example
  const validationResult = await validate([
    validations.string.isString('foo', 'fooValue'),
    validations.number.isNotZero('bar', 0),
  ]);
  console.log(validationResult); // prints { isValid: true, fields: ["Field 'bar', expected not to be Zero. Got 0"] }

  // custom validation example
  const customValidator = (prop, value) => {
    const onFailureMessage = `Field '${prop}', is not valid`;
    return {
      validation: 'myCustomValidation', // validation name
      property: prop,
      onFailureMessage,
      execute: () => value !== undefined,
    };
  };

  const customValResult = await validate([customValidator('name', undefined)]);
  console.log(customValResult); // prints { isValid: false, fields: [ "Field 'name', is not valid" ] }
})();