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Isomorphic validation javascript library ISOMORPHIC-VALIDATION

Execution environment separation

Execution environment separation here is a way of running particular predicate functions and state callbacks only in the specified environment and is implemented with the aid of the following properties:

State callbacks separation

For example, asuming you use the same validation logic on both sides, on the client side you might need to perform UI effects connected to validations’ states, whereas on the server side logging on “invalid” to detect attempts to get around your client side validations. If the client side validations passed, the server side validations cannont fail.

import { disableElement, enableElement } from 'your-ui-effects-file.js';
import { log } from 'your-logging-tools-file.js';
// import predicate functions from your-predicates-file.js
// ...


const loginV = Validation();
const passwordV = Validation();


// adding constraints to loginV and passwordV
// loginV.constraint() ...
// passwordV.constraint() ...
// ...


// creating a validation profile
const [signinForm, signinV] = Validation.profile(
    '[name=signinForm]',
    ['login', 'password'],
    [loginV, passwordV],
);


signinV
    .client
    .started(disableElement(signinForm.submitBtn)) // ignored on the server side
    .invalid(disableElement(signinForm.submitBtn)) // ignored on the server side
    .valid(enableElement(signinForm.submitBtn))    // ignored on the server side
    .server
    .invalid(log);                                 // ignored on the client side


// export validation to use on the server side as a middleware function
export default signinV;

Constraints separation

In some cases it may be useful to split a predicate function in two parts and execute one on the client and the other one on the server side.

import {
    isEmailNotTemp,
    isEmailVacantC, // makes a request to the server
    isEmailVacantS, // makes a request to a database
    // other predicate functions
    // ...
} from 'your-predicates-file.js';


const emailV = Validation();
const passwordV = Validation();
const pwdconfirmV = Validation();


// adding shared constraints to emailV, passwordV and pwdconfirmV
// loginV.constraint() ...
// passwordV.constraint() ...
// pwdconfirmV.constraint() ...
// ...


// creating a validation profile
const [signupForm, signupV] = Validation.profile(
    '#signup_form',
    ['email', 'password', 'pwdconfirm'],
    [emailV, passwordV, pwdconfirmV]
);


// adding form-specific constraints
signupV.email
    .constraint(isEmailNotTemp)         // will be added on both sides
    .client.constraint(isEmailVacantC)  // will be added only on the client side
    .server.constraint(isEmailVacantS); // will be added only on the server side


// export validation to use on the server side as a middleware function
export default signupV;

Now assuming isEmailVacantC makes a request to the '/chkemail' url, the server code may look as following:

import express from 'express';
import bodyParser from 'body-parser';
import signinV from 'your-signin-validation-file-name.js';
import signupV from 'your-signup-validation-file-name.js';
import {
    signinRequestHandler,
    signupRequestHandler,
    checkemailRequestHandler,
} from 'your-file-name.js';


const app = express();
const urlencodeParser = bodyParser.urlencoded({extended: false});


// validations are added as middleware functions
app.post('/signin', urlencodeParser, signinV, signinRequestHandler);
app.post('/signup', urlencodeParser, signupV, signupRequestHandler);
app.post('/chkemail', urlencodeParser, signupV.email, checkemailRequestHandler);