Installation

npm install --save mongoose-validation-helper

Why

I wrote this package because I was tired of writing code that took mongoose validation errors and mapped them to form fields. It's not complicated but it is tedious.

This was written to work with a form submitted via jQuery $.ajax and rendered by React. It should work elsewhere, but I dunno; it's so simple that I don't think there's any bias towards any particular library.

How

mongoose schema validation errors look something like:

{
  "message": "Validation failed",
  "name": "ValidationError",
  "username": {
    "message": "some validation rule failed",
    "path": "username",
    "name": "ValidatorError",
    "type": "user defined",
    "value": "whatever value you tried to sneak in"
  }
}

Here's how you might use it with ajax and React. This is a totally incomplete example, of course, but I hope it's helpful to see it in context.

var React = require('react');
var validationHelper = require('mongoose-validation-helper');
module.exports = LoginForm = React.createClass({
  handleSubmit: function(e) {
    e.preventDefault();

    var formdata = {
      username: this.refs.username.getDOMNode().value.trim(),
      password: this.refs.password.getDOMNode().value.trim()
    };

    $.ajax({
      url: '/login',
      dataType: 'json',
      type: 'POST',
      data: formdata,
      success: function(data) {
        // reload the page, redirect the user, whatever.
      },
      error: function(xhr, status, err) {

        // I'm going to be showing an error message for each field using React,
        // specifically through an object at this.state.error. I don't care
        // about any "extra" fields mongoose may have returned, in this case.

        var updatedState = {error: {}};

        validationHelper.parse(xhr.responseJSON, formdata, function(result, extras) {
          updatedState.error = result;
        });

        this.setState(updatedState);
      }.bind(this)
    });
  },

  render: function() {
    return(
      <div className="login-form">
        <form onSubmit={this.handleSubmit} method="post">
          <input type="text" ref="username">
          {this.state.error.username ? <span>{this.state.error.username}</span> : ''}
          <input type="text" ref="password">
          {this.state.error.password ? <span>{this.state.error.password}</span> : ''}
          <input type="submit" value="Log in"/>
        </form>
      </div>
    )
  }
});