@briza/wegood

wegood

Tiny validation library, so wegood with data.

Revision: January 29, 2020.

About

This project has been developed to provide a shared validation logic between front-end and back-end code, easily extend-able with custom rules.

• It is unit tested with 100% code coverage.
• Easily localized validation messages.
• Plug & play custom validation rules.
• Not dependent on any library.
• Readable and declarative validation rules.

The library is being build as CommonJS module and ESM.

Code documentation could be found here: https://briza-insurance.github.io/wegood/index.html.

Installation via NPM or Yarn

npm install -D @briza/wegood

yarn add @briza/wegood -D

Table of Content

---

• Basic Usage
  • Validator Methods
    • Rules
    • Validate
      • Validation Result
    • Valid
    • Errors
• Builtin Validation Rules
  • Present
  • Equal
  • Pattern
  • Range
  • Length
  • Exclude
  • Include
  • Date
    • Relative Date Offset
    • Date Tested Value Format
• Custom Validation Rule
• Contributing
  • Pull Request Process
• License

---

Basic Usage

// Import the Validator.
import Validator from '@briza/wegood';

// Import some of the predefined validation rules.
import {
  equal,
  length,
  pattern,
} from '@briza/wegood';

/**
 * Create a new instances of the validator with given rules.
 */

const ratingValidator = new Validator([
  present('The rating is required.'),
  equal('The value must be 5.', 5)
]);

const idValidator = new Validator([
  present('The ID is required.'),
  length('The value must 9 characters long.', 9, 9),
  pattern('The value must be in A000-0000 format, where 0 could be any number.', /^A\d{3}-\d{4}$/)
]);

/**
 * Use one of the validation methods.
 */

// Return the validation result:
// { valid: boolean, errors: [] }
// Errors contains the error message of the first not-satisfied rule.
ratingValidator.validate(1);

// Return the validation result:
// { valid: boolean, errors: [] }
// Errors contains the error message of all not-satisfied rules.
idValidator.validate('a1234-4', false /* firstErrorOnly */);

// Return true if valid, false otherwise.
ratingValidator.valid(1);

// Return array of error messages of all not-satisfied rules.
idValidator.errors('a1234-4');

// Return array of error messages of all not-satisfied rules.
idValidator.errors('a1234-4');

// Return only the first error message of the not-satisfied rule, still returned as an array.
idValidator.errors('a1234-4', true /* firstErrorOnly */);

Validator Methods

// Import the Validator.
import Validator from '@briza/wegood';
import { present } from '@briza/wegood';

// Create the validator.
const validator = new Validator([present('this field is required.')]);

There is collection of functions to provide implementation agnostic approach:

Rules

Get the validator rules.

Code documentation.

validator.rules
// validation rules (function[])

Validate

Validate against the tested value, it returns the Validation Result.

Validation Result

The Validation Result is a object with these properties:

Property	Type	Note	Example
valid	boolean	Validity state.	true
errors	string[]	Collection of captured validation errors.	['this field is required']

Example

// Valid
{
  valid: true,
  errors: []
}

// Invalid
{
  valid: false,
  errors: ['invalid email format']
}

---

Passing false as the seconds parameter, returns collection of all validation errors, if any.

Code documentation.

validator.validate(testedValue)
/**
 * {
 *  valid: true|false,
 *  errors: []
 * }
 * 
 * The errors will contain only first discovered error.
 * 
 */

validator.validate(testedValue, false)
/**
 * {
 *  valid: true|false,
 *  errors: []
 * }
 * 
 * The errors will contain all discovered error.
 * 
 */

Valid

Validity predicate against the tested value.

Code documentation.

validator.valid(testedValue)
// true | false

Errors

Get the validation errors. if any.

Code documentation.

Passing true as the seconds parameter, returns only the first validation error, if any.

validator.errors(testedValue)
// string[]
// All errors will be captured.

validator.errors(testedValue, true)
// string[]
// Only the first error will be captured.

Builtin Validation Rules

All builtin validation rules have this construct:

function rule(errorMessage: string, agr1: any, ... argN: any): (value: any) => true|string

• A function which returns the validation rule function with set error message, plug-able into the Validator, or it could be used individually, e.g. rule('error message')(testValue).
• The args differs form rule to rule.
• Please see Custom Validation Rule for more information.

Present

Verify that the tested value is present, i.e. defined and not empty.

import { present } from '@briza/wegood';

Function Arguments

present(errorMessage)

Argument	Notes	Example
errorMessage	Error message.	'the value must be 5'

Code documentation.

• Non-empty array tested value is evaluated as valid.
• Empty string tested value is evaluated as invalid.
• Object, Function tested value throws an error.

Example

// The value must have some value.
present('error message');

Equal

Verify that the tested value is equal to another.

import { equal } from '@briza/wegood';

Function Arguments

equal(errorMessage, value|customMatcher)

Argument	Notes	Example
errorMessage	Error message.	'the value must be 5'
value	The equal value.	5
customMatcher	Custom equality predicate function.	(value) => value === 5

Code documentation.

Example

// The value must be equal to 5.
equal('error message', 5);

// Custom matcher.
equal('error message', (value) => {
  return value === 5;
});

Pattern

Verify that the tested value is matches the pattern.

import { pattern } from '@briza/wegood';

Function Arguments

pattern(errorMessage, pattern)

Argument	Notes	Example
errorMessage	Error message.	'invalid email format'
pattern	Regular expression used to validate the value.	/^[^@]+@.*\.[a-z]{2, 5}$/

Code documentation.

Example

// The value must match the given pattern.
pattern('error message', /^[^@]+@.*\.[a-z]{2, 5}$/);

Range

Verify that the tested value is in the given range (inclusive).

• Applicable only on the number values, although the rule auto-converts string into number if it is a valid number.
• Could be also used as MAX and MIN.

import { range } from '@briza/wegood';

Function Arguments

range(errorMessage, min, max)

Argument	Notes	Example
errorMessage	Error message.	'the value must be in range 3-10'
min	Minimal boundary. If set to undefined or null, it is being ignored.	3
max	Maximal boundary. If set to undefined or null, it is being ignored.	10

Code documentation.

Example

// The value must be between 3 and 10.
range('error message', 3, 10);

// The value must be 3 and above, aka MIN.
range('error message', 3);

// The value must be 10 and bellow, aka MAX.
range('error message', null|undefined, 10);

Length

Verify that the tested value is in the given string length range (inclusive).

• Applicable only on the string values, although the rule auto-converts numbers into strings.
• Could be also used as MAX and MIN.

import { length } from '@briza/wegood';

Function Arguments

length(errorMessage, min, max)

Argument	Notes	Example
errorMessage	Error message.	'the value must be 3-10 characters long'
min	Minimal length. If set to undefined or null, it is being ignored.	3
max	Maximal length. If set to undefined or null, it is being ignored.	10

Code documentation.

Example

// The value must be 3 up to 10 characters long.
length('error message', 3, 10);

// The value must be 3 and more characters long, aka MIN.
length('error message', 3);

// The value must be 10 and less characters long, aka MAX.
length('error message', null|undefined, 10);

Exclude

Verify that the tested value is not the exclusion list.

import { exclude } from '@briza/wegood';

Function Arguments

exclude(errorMessage, exclusions)

Argument	Notes	Example
errorMessage	Error message.	'invalid value'
exclusions	Array of exclusions.	[1,2,3]

Code documentation.

Example

// The value must not be contained in the list.
exclude('error message', [1, 2, 3]);

// The value must not be contained in the list.
exclude('error message', ['circle', 'square', 'triable']);

Include

Verify that the tested value is not the exclusion list.

import { include } from '@briza/wegood';

Function Arguments

include(errorMessage, inclusions)

Argument	Notes	Example
errorMessage	Error message.	'invalid value'
inclusions	Array of inclusions.	[1,2,3]

Code documentation.

Example

// The value must be contained in the list.
include('error message', [1, 2, 3]);

// The value must be contained in the list.
include('error message', ['circle', 'square', 'triable']);

Date

Verify that the tested value is the date range.

import { date } from '@briza/wegood';

Function Arguments

date(errorMessage, start, end, transform)

Argument	Notes	Example
errorMessage	Error message.	'the date in not in valid range.'
start	Start date boundary - ISO date string (yyyy-mm-dd), Date object, or Relative Date Offset. If set to undefined or null, it is being ignored.	3
end	End date boundary - ISO date string (yyyy-mm-dd), Date object, or Relative Date Offset. If set to undefined or null, it is being ignored.	3
transform	Custom Date object transformer function. Optional.	(value) => new Date(value)

Code documentation.

Relative Date Offset

Instead of a concrete ISO date string or Date object below annotated shortcodes might be used to set the date boundary relative to TODAY date.

Annotation	Meaning	Example
0	Today.	0
-1	In past.	-1
1	In future.	1
-Nd	N days in past, relative from today.	-10d
Nd	N days in past, relative from today.	10d
-Nw	N weeks in past, relative from today.	-2w
Nw	N weeks in past, relative from today.	2w
-Nm	N months in past, relative from today.	-6m
Nm	N months in past, relative from today.	6m
-Ny	N years in past, relative from today.	-2y
Ny	N years in past, relative from today.	2y

Example

/**
 * The value (date) must between the given data range.
 */
// ISO strings
date('error message', '2000-12-30', '2020-06-29');
// Date objects
date('error message', new Date('2000-12-30T00:00:00+00:00'), new Date('2020-06-29T00:00:00+00:00'));

/**
 * The value (date) must after the date.
 */
// ISO string
date('error message', '2000-12-30');
// Date object
date('error message', new Date('2000-12-30T00:00:00+00:00'))

/**
 * The value (date) must before the date.
 */
// ISO string
date('error message', undefined|null, '2020-06-29');
// Date object
date('error message', undefined|null, new Date('2020-06-29T00:00:00+00:00'))

/**
 * Relative offsets, relative to today.
 */

// Any date in past, until today.
date('error message', -1, 0);

// Any date in future, starts from today.
date('error message', 0, 1);

// Any date between 2 years ago, up to 3 months from today.
date('error message', '-2y', '3m');

// Combined fixed date with relative date.
// Any date from 2000-12-30 until today.
date('error message', '2000-12-30', 0);

Date Tested Value Format

The tested value must be passed to the validation rule in the ISO date string (yyyy-mm-dd) or as a Date object, otherwise the validation rule throws an error. The transform function could be passed to the rule to handle custom conversion from mixed value into the Date object.

// Custom transform function
date('error message', '2000-12-30', '2020-06-29', (value) => new Date(value));

Custom Validation Rule

Validation rule blueprint (typescript):

function email(errorMsg: string): ValidationRule {
  const rx = /^[^@]+@.*\.[a-z]{2,5}$/
  return (value: any): true|string {
    // Invalid value
    if (value.match(rx) === null) {
      return errorMsg
    }
    // Valid value
    return true
  }
}

• ValidationRule (typescript type), represents: (value) => true|string, where:
  • true = valid.
  • string = error message.

---

Contributing

When contributing to this repository, please first discuss the change you wish to make via issue, email, or any other method with the owners of this repository before making a change.

Pull Request Process

1. Fork it
2. Create your feature branch (git checkout -b ft/new-feature-name)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin ft/new-feature-name)
5. Create new Pull Request

Please make an issue first if the change is likely to increase.

License

wegood is released under the MIT license. See LICENSE.txt.