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" ] }
})();