Easy input validation with form validator

This library will help you validate any strings (emails, passwords, URLs, etc) and show an error if the validation fails.

Features:

• Small size.
• No extra npm dependecies.
• Typescript support.
• Full test coverage.
• Support all platforms.

Table of contents

• Quick start
• Usage example
  • React
• Settings
• Typescript
• Bug reporting
• Support

Quick start

For start using:

npm i simple-string-validator

or

yarn add simple-string-validator

Usage example

React:

import React, { useState } from 'react';
import validate from 'simple-string-validator';

function InputValidation() {
  const [email, setEmail] = useState('');
  const [emailErrors, setEmailErrors] = useState<string[] | null>();

  const submitForm = (e: React.ChangeEvent<HTMLFormElement>) => {
    e.preventDefault();
    setEmailErrors(null);
    const { errors } = validate(email, { isEmail: true, required: true });
    if (errors) {
      setEmailErrors(errors);
      return;
    }
    //submit form logic
  };

  return (
    <form onSubmit={submitForm}>
      <h1>Enter your email to subscribe.</h1>
      <input value={email} onChange={(e) => setEmail(e.target.value)} />
      {emailErrors &&
        emailErrors.map((error) => {
          return <p>{error}</p>;
        })}
      <button>Submit</button>
    </form>
  );
}

export default InputValidation;

You could get all the validation errors from the "errors" array.

You could also provide your custom error message (see accepted parameters below).

Settings

Parameter	Type	Description
maxLength	number	Sets the maximum allowed string length.
minLength	number	Sets the minimum allowed string length.
required	boolean	Indicates whether this string is required
numbersOnly	boolean	A flag that indicates that only numbers should be contained in the string.
lettersOnly	boolean	A flag that indicates that only letters should be contained in the string.
lettersAndNumbersOnly	boolean	A flag that indicates that only numbers and letters should be contained in the string. Special characters are not allowed.
case	"lower", "upper", "both required"	Sets the case in which the string should be
containSpecialCharacters	boolean	Indicates that the string must contain special characters.
isEmail	boolean	Checks if a string is an email
isURL	boolean	Checks if a string is an URL
errorMessage	string	Allows you to set a custom error message that will be displayed if the string fails validation.

Custom error messages example:

const { errors } = validate(email, {
      isEmail: true,
      required: true,
      errorMessage: 'Please, provide correct email'
    })

Typescript

This library has full Typescript support.

Bug reporting

You could send it to achekhovskoi@gmail.com or open an issue on https://github.com/ArtemChekhovskoi/form-validate/issues.

License

ISC Licensed. Artem Chekhvskoi, 2023.

Keywords

validate form inputs string validation validator password email