ExpressWebJS

# Validation

ExpressWebJs makes it easy to validate user input with the help of it's validation feature, let's look at a complete example of validating a form and displaying the error messages back to the user.

# Defining The Routes

First, let's assume we have a post route defined in our Routes/api.ts file:

Route.post("post", "UserController@store");

The POST route will store user data in the database.

# Writing The Validation Logic

To create our validation to validate user data, we do that with the Maker command

  ts-node maker make-request UserValidator

This will generate our UserValidator class in App/Http/Requests folder. If this folder is not there, it will create it for us.

Our generated UserValidator class in UserValidator_request.ts file looks like so:

"use strict";
import FormRequest from "Elucidate/Validator/FormRequest";

class UserValidator {
  /**
   * Handle the request validation.
   * @param {*} data | e.g request body
   */
  async validate<T>(data: T) {
    return await FormRequest.make(data, {
      //validation rules.
    });
  }
}

export default new UserValidator();

We can now create our validation rules in the validation rules section in validate method like so:

"use strict";
import FormRequest from "Elucidate/Validator/FormRequest";

class UserValidator {
  /**
   * Handle the request validation.
   * @param {*} data | e.g request body
   */
  async validate<T>(data: T) {
    return await this.make(data, {
      first_name: "required|string",
      last_name: "required|string",
      phone: "required|max:14",
      email: "required|string|email|max:255",
      country: "required|string|max:255",
      city: "required|string|max:255",
      industry: "required|string|max:255",
    });
  }
}

export default new UserValidator();

# Using validation in controller

We can now use our UserValidator in UserController like so:

"use strict";
import userValidator from "App/Http/Requests/userValidator_request";
import { Request, Response, NextFunction } from "Elucidate/HttpContext";
import HttpResponse from "Elucidate/HttpContext/ResponseType";

class UserController {
  store = async (req: Request, res: Response, next: NextFunction) => {
    try {
      let validate = await userValidator.validate(req.body);
      if (!validate.success) return HttpResponse.BAD_REQUEST(res, validate);

      //continue processing your data
    } catch (error) {
      return next(error);
    }
  };
}

export default UserController;

# Inline validation

We can also perform inline validation in our controller like so:

"use strict";
import { Request, Response, NextFunction } from "Elucidate/HttpContext";
import HttpResponse from "Elucidate/HttpContext/ResponseType";

class UserController {
  store = async (req: Request, res: Response, next: NextFunction) => {
    try {
      let validate = await req.validate(req.body, {
        first_name: "required|string",
        last_name: "required|string",
        phone: "required|max:14",
        email: "required|string|email|max:255",
        country: "required|string|max:255",
        city: "required|string|max:255",
        industry: "required|string|max:255",
      });
      if (!validate.success) return HttpResponse.BAD_REQUEST(res, validate);

      //continue processing your data
    } catch (error) {
      return next(error);
    }
  };
}

export default UserController;

# Working With Nested Rules

Nested objects can also be validated. There are two ways to declare validation rules for nested objects. The first way is to declare the validation rules with a corresponding nested object structure that reflects the data. The second way is to declare validation rules with flattened key names. Let's say our request data looks like so:

let data = {
  name: "Alex",
  bio: {
    age: 27,
    education: {
      primary: "Elementary School",
      secondary: "Secondary School",
    },
  },
};

We could declare our validation rules as follows:

"use strict";
import FormRequest from "Elucidate/Validator/FormRequest";

class UserValidator {
  /**
   * Handle the request validation.
   * @param {*} data | e.g request body
   */
  async validate<T>(data: T) {
    return await this.make(data, {
      name: "required",
      bio: {
        age: "min:18",
        education: {
          primary: "string",
          secondary: "string",
        },
      },
    });
  }
}

export default new UserValidator();

# Or using flattened key names

"use strict";
import FormRequest from "Elucidate/Validator/FormRequest";

class UserValidator {
  /**
   * Handle the request validation.
   * @param {*} data | e.g request body
   */
  async validate<T>(data: T) {
    return await this.make(data, {
      name: "required",
      "bio.age": "min:18",
      "bio.education.primary": "string",
      "bio.education.secondary": "string",
    });
  }
}

export default new UserValidator();

# WildCards Rules

WildCards can also be validated.

"use strict";
import FormRequest from "Elucidate/Validator/FormRequest";

class UserValidator {
  /**
   * Handle the request validation.
   * @param {*} data | e.g request body
   */
  async validate<T>(data: T) {
    return await this.make(data, {
      "users.*.name": "required",
      "users.*.bio.age": "min:18",
      "users.*.bio.education.primary": "string",
      "users.*.bio.education.secondary": "string",
    });
  }
}

export default new UserValidator();

# Regex validation

In regex validation, the field under validation must match the given regular expression.

Note: When using the regex pattern, it may be necessary to specify rules in an array instead of using pipe delimiters, especially if the regular expression contains a pipe character. For each backward slash that you used in your regex pattern, you must escape each one with another backward slash.

"use strict";
import FormRequest from "Elucidate/Validator/FormRequest";

class UserValidator {
  /**
   * Handle the request validation.
   * @param {*} data | e.g request body
   */
  async validate<T>(data: T) {
    return await this.make(data, {
      name: "required|size:3",
      salary: ["required", "regex:/^(?!0\\.00)\\d{1,3}(,\\d{3})*(\\.\\d\\d)?$/"],
      yearOfBirth: ["required", "regex:/^(19|20)[\\d]{2,2}$/"],
    });
  }
}

export default new UserValidator();

# Type Checking Validation

"use strict";
import FormRequest from "Elucidate/Validator/FormRequest";

class UserValidator {
  /**
   * Handle the request validation.
   * @param {*} data | e.g request body
   */
  async validate<T>(data: T) {
    return await this.make(data, {
      age: ["required", { in: [29, 30] }],
      name: [{ required_if: ["age", 30] }],
    });
  }
}

export default new UserValidator();

# Custom Error Messages

If you need a specific error message and you don't want to override the default one, you can pass an override as the third argument to the make object.

"use strict";
import FormRequest from "Elucidate/Validator/FormRequest";

class UserValidator {
  /**
   * Handle the request validation.
   * @param {*} data | e.g request body
   */
  async validate<T>(data: T) {
    return await this.make(
      data,
      {
        name: "required",
      },
      { required: "You forgot to give a :attribute" },
    );
  }
}

export default new UserValidator();

If the validation failes, the error message will be 'You forgot to give a name'.

Some of the validators have string and numeric versions. You can change them too.

"use strict";
import FormRequest from "Elucidate/Validator/FormRequest";

class UserValidator {
  /**
   * Handle the request validation.
   * @param {*} data | e.g request body
   */
  async validate<T>(data: T) {
    return await this.make(
      data,
      {
        username: "max:16",
      },
      {
        max: {
          string: "The :attribute is too long. Max length is :max.",
        },
      },
    );
  }
}

export default new UserValidator();

If the validation failes, the error message will be 'The username is too long. Max length is 16.'

You can even provide error messages on a per attribute basis! Just set the message's key to 'validator.attribute'

"use strict";
import FormRequest from "Elucidate/Validator/FormRequest";

class UserValidator {
  /**
   * Handle the request validation.
   * @param {*} data | e.g request body
   */
  async validate<T>(data: T) {
    return await this.make(
      data,
      {
        email: "required",
      },
      { "required.email": "Without an :attribute we can't reach you!" },
    );
  }
}

export default new UserValidator();

If the validation failes, the error message will be "Without an email we can't reach you!"

# Available Validation Rules

Below is a list of all available validation rules and their function:

Note: Validation rules do not have an implicit 'required'. If a field is undefined or an empty string, it will pass validation. If you want a validation to fail for undefined or '', use the required rule.

Rule Function
accepted The field under validation must be yes, on, 1 or true. This is useful for validating "Terms of Service" acceptance.
after:date The field under validation must be after the given date.
after_or_equal:date The field unter validation must be after or equal to the given field.
alpha The field under validation must be entirely alphabetic characters.
alpha_dash The field under validation may have alpha-numeric characters, as well as dashes and underscores.
alpha_num The field under validation must be entirely alpha-numeric characters.
array The field under validation must be an array.
before:date The field under validation must be before the given date.
before_or_equal:date The field under validation must be before or equal to the given date.
between:min,max The field under validation must have a size between the given min and max. Strings, numerics, and files are evaluated in the same fashion as the size rule.
boolean The field under validation must be a boolean value of the form true, false, 0, 1, 'true', 'false', '0', '1'
confirmed The field under validation must have a matching field of foo_confirmation. For example, if the field under validation is password, a matching password_confirmation field must be present in the input.
date The field under validation must be a valid date format which is acceptable by Javascript's Date object.
digits:value The field under validation must be numeric and must have an exact length of value.
digits_between:min,max The field under validation must be numeric and must have length between given min and max.
different:attribute The given field must be different than the field under validation.
email The field under validation must be formatted as an e-mail address.
hex The field under validation should be a hexadecimal format. Useful in combination with other rules, like hex|size:6 for hex color code validation.
in:foo,bar,... The field under validation must be included in the given list of values. The field can be an array or string.
integer The field under validation must have an integer value.
max:value Validate that an attribute is no greater than a given size
min:value Validate that an attribute is at least a given size.
not_in:foo,bar,... The field under validation must not be included in the given list of values.
numeric Validate that an attribute is numeric. The string representation of a number will pass.
present The field under validation must be present in the input data but can be empty.
required The field under validation must be present in the input data and not empty.
required_if:anotherfield,value The field under validation must be present and not empty if the anotherfield field is equal to any value.
required_unless:anotherfield,value The field under validation must be present and not empty unless the anotherfield field is equal to any value.
required_with:foo,bar,... The field under validation must be present and not empty only if any of the other specified fields are present.
required_with_all:foo,bar,... The field under validation must be present and not empty only if all of the other specified fields are present.
required_without:foo,bar,... The field under validation must be present and not empty only when any of the other specified fields are not present.
required_without_all:foo,bar,... The field under validation must be present and not empty only when all of the other specified fields are not present.
same:attribute The given field must match the field under validation.
size:value The field under validation must have a size matching the given value. For string data, value corresponds to the number of characters. For numeric data, value corresponds to a given integer value.
string The field under validation must be a string.
url Validate that an attribute has a valid URL format.
regex:pattern The field under validation must match the given regular expression.

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