wegood

Tiny validation library, so wegood with data.

Revision: March 22, 2022.

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
  • Year
    • Relative Year Offset
    • Year 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.	2020-03-16
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.	3y
transform	Custom Date object transformer function. Optional.	(value) => new Date(value)
todayDate	Today's date to be used for relative date boundaries. Optional, if not provided the start of the day in current environment timezone will be used	new Date('2020-10-10T00:00:00+03:00)

Code documentation.

Relative Date Offset

Instead of a concrete ISO date string or Date object below annotated shortcodes may 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);

// Passing today Date
date(
  "error message",
  1,
  "60d",
  undefined,
  new Date("2020-11-11T00:00:00+03:00")
);

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));

Year

Verify that the tested value is in the year range.

import { year } from "@briza/wegood";

Function Arguments

year(errorMessage, start, end);

Argument	Notes	Example
errorMessage	Error message.	'the year in not in valid range.'
start	Start date boundary: 4-digit year number or Relative Year Offset. If set to undefined or null, it is being ignored.	2000
end	End date boundary: 4-digit year number or Relative Year Offset. If set to undefined or null, it is being ignored.	3y

Code documentation.

Relative Year Offset

Instead of a concrete year below annotated shortcodes may be used to set the year boundary relative to the CURRENT year.

Annotation	Meaning	Example
0	Current year.	0
-1	In past.	-1
1	In future.	1
-Ny	N years in past, relative from current year.	-2y
Ny	N years in past, relative from current year.	2y

Example

// The value (year) must between the given years range.
year("error message", 2000, 2020);

// The value (year) must after the year (inclusive).
year("error message", 2000);

// The value (year) must before the year (inclusive).
year("error message", undefined | null, 2020);

/**
 * Relative offsets, relative to current year.
 */

// Any year in past, until current year.
year("error message", -1, 0);

// Any year in future, starts from current year.
year("error message", 0, 1);

// Any year between 2 years ago, up to 2 years from current year.
year("error message", "-2y", "2y");

// Combined fixed year with relative year.
// Any year from 2000 until current year.
year("error message", 2000, 0);

Year Tested Value Format

The tested value must be passed to the validation as non zero number (string or number), otherwise the validation will fail implicitly with warning message.

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

See contributing.md.

License

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