INTRO

A simple, schema-structured javascript data validator.

Can be easily used both client side and server side. This is created as a generic and independent validation solution for use in any context.

Works in any typescript and javascript project.

Installation

npm i hgvalidator --save

Usage

Import the module

import Validator from 'hgvalidator'

Some data to validate (These may have been extracted directly from forms or sent as request body to the server)

let title = '   '
let content = 'Some long wysiwyg content'
let username = user123
let random = 78


// A variable to store the validation errors, if any..
let validationErrors = null

Every validation requires a SCHEMA which must be an array of objects like in the example below.

const schema = [
	{
		fieldName: 'Title', //Required as custom reference to the validated field.
		data: title,	//The data to validate
		rules: {
			required: true,
			string: true,
			max: 200	// The min/max rules work for both strings (returns characters length), and numbers (returns digit size).
		},
		messages: { //Optional. Add some custom validation messages if necessary.
			max: 'Title should not be more than 200 characters'
		}
	},
	{
		fieldName: 'Content',
		data: content,
		rules: {
			required: true,
		},
	},
	{
		fieldName: 'Username',
		data: username,
		rules: {
			required: true,
			pattern: /^([a-zA-Z]{4,})([0-9])*$/
		},
		message:{
			pattern: 'blah blah blah'
		}
	},
	{
		fieldName: 'Random',
		data: random,
		rules: {
			required: true,
			min: 100
		},
	}
]

See all default supported validation rules

Validate the data

const validated = Validator.validate(schema, { skip: ['Content'] })

	/*	The "skip" option prevents validation of the fields names listed in the array. This is Useful when using same schema for multiple validations
	*/

if(validated) {
	console.log('success')
	// preceed with other stuffs
}
else {
	validationErrors = Validator.getErrors()

	// Validator.getErrors() returns an object (contaning the first error of each validated field) by default..
	// Result:
		{
			Title: "Title is required and cannot be empty",
			Random: "Random value should not be less than 100",
		}

	//If you'd like to get back only one error, use the {"format:'single'}" option.
	validationErrors = Validator.getErrors({format: 'single'})
		// Result:
		"Title is required and cannot be empty"

}

Then in the html (if validating a form)

<input id="title" name="title" />
<span id="titleErrorMsg">{{ titleErrorMsg }}</span>
...
...
...
...

<script>
...
...
	document.querySelector('#titleErrorMsg').innerText = validationErrors['Title']
</script>

Available utility methods

- Validator.validate(schema, options = {}) //This has been explained above


- Validator.sanitize(data, options = {}) // for personally stripping out all html tags and trimming empty spaces in data.
		/*Sanitize options */
		const options = {
			strict: false // defaults to 'true'.
					/* 	If false, only '<script>' tags will be removed from the data, other tags will be left.
						And only beginning and ending whitespaces will be removed. */
		}


- Validator.getErrors() // returns validation errors

Supported_Rules

rules: {
	required: boolean
	string: boolean
	email: boolean
	number: boolean
	min: number
	max: number
	equalTo: any
	pattern: RegExp
}

disclaimer

Please note that no guarantee of any kind is granted with the use of this code.