express-validator-helper

    1.0.1 • Public • Published

    express-validator-helper

    img img img img img img

    Simple express-validator wrapper for easier work with validation error handling.

    img

    Installation

    $ npm i express-validation-helper -S
    // add expressValidator before helper
    app.use(expressValidator());
    app.use(expressValidatorHelper());

    Usage

    Just do a check with express-validator as usual. Then instead req.validationErrors(true) call req.validate(). This method returns a Validator object.

    Validator object

    add(fieldName, msg)

    Add error with msg to fieldName.

    isValid()

    Returns true if all data is valid. Otherwise false.

    errors

    Object with all validation errors. It should be used only if the isValid method returns false.

    Values contain an array with a list of errors. Example:

    {
      email: ['required', 'invalid format', 'already taken'],
      password: ['required']
    }

    Customization

    You can pass name option to middleware with a custom method name:

    app.use(expressValidatorHelper({
      name: 'doValidate'
    });
     
    // ...
     
    var validator = req.doValidate();

    Before & After

    Confirmation handler example.

    Before

    exports.create = function(req, res, next) {
      // checks with reverse order
      req.assert('email', 'invalid format').isEmail();
      req.assert('email', 'required').notEmpty();
     
      var errors = req.validationErrors(true);
      var email = req.body.email;
     
      return User.findOne({
        email: new RegExp('^' + email + '$', 'i')
      }, function(err, user) {
        if (err) { return next(err); }
     
        if (user && user.isEmailConfirmed === true && !errors.email) {
          errors = errors || {};
          errors.email = {
            param: 'email',
            msg: 'you account already confirmed',
            value: email
          };
        }
     
        if (!user && !errors.email) {
          errors = errors || {};
          errors.email = {
            param: 'email',
            msg: 'user with that email not found'
          };
        }
     
        if (!_.isEmpty(errors)) {
          return res.render('confirmations/new', {
            errors: errors,
            values: req.body
          });
        }
     
        // ... success
      });
    };

    After

    exports.create = function(req, res, next) {
      // checks with normal order
      req.assert('email', 'required').notEmpty();
      req.assert('email', 'invalid format').isEmail();
     
      // call validate method on `req` object
      var validator = req.validate();
      var email = req.body.email;
     
      return User.findOne({
        email: new RegExp('^' + email + '$', 'i')
      }, function(err, user) {
        if (err) { return next(err); }
     
        if (user && user.isEmailConfirmed === true) {
          // add errror for email field
          validator.add('email', 'you account already confirmed');
        }
     
        if (!user && !errors.email) {
          validator.add('email', 'user with that email not found')
        }
     
        // check if user data is not valid
        if (!validator.isValid()) {
          return res.render('confirmations/new', {
            errors: validator.errors,  // pass errors property to views
            values: req.body
          });
        }
     
        // ... success
      });
    };

    Reason

    express-validator (Validator.js middleware for Express.js) is wonderful tool for validating user input. But it does not allow to define custom async validators. For example we want to check if email is already taken on signup page. Ok, we can add errors manually to req.validationErrors() result. And here we are faced with several problems:

    req.validationErrors() result

    express-validator provides two ways to get a result - as an array or object.

    Array is not very useful if you want to display an error for each field separately. It is not for us.

    Object contains only the last error:

    req.assert('email', __('required')).notEmpty();
    req.assert('email', __('invalid format')).isEmail();
     
    var errors = req.validationErrors(true);

    Here the errors will contain message for format validation instead notEmpty() check. So you have to do the checking in reverse order. This is the first problem.

    Adding errors

    req.validationErrors(true) can return null or object with errors and we should check it. Also error for a particular field may already be in the object and we should check it too:

    req.assert('email', __('invalid format')).isEmail();
    req.assert('email', __('required')).notEmpty();
     
    var errors = req.validationErrors(true);
     
    User.findOne({ email: req.body.email }, function(err, existsUser) {
      if (err) { return next(err); }
     
      if (existsUser && !errors.email) {
        errors = errors || {};
        errors.email = {
          param: 'email',
          msg: 'already taken',
          value: req.body.email
        }
      }
    });

    If we do not check this, our error will appear even when unfilled or incorrect e-mail address.

    It becomes routine, when we do more of checks like this.

    Tests

    • npm test
    • npm run-script test-cov

    License

    MIT

    Install

    npm i express-validator-helper

    DownloadsWeekly Downloads

    0

    Version

    1.0.1

    License

    MIT

    Last publish

    Collaborators

    • avatar