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 [email protected] 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