joi-errors-for-forms

joi-errors-for-forms

In order to keep a consistent validation API in your apps, convert the error objects returned by Joi to either

• the { name1: text, name2: text } schema commonly used with form UIs, or
• the Mongoose schema { name1: { message: ..., name: 'ValidatorError', path: ..., type: ... } }.

The Joi error messages may be replaced either for internationalization or clarity.

The package has no dependencies.

Code Examples

For the following Joi schema:

const Joi = require('joi');
const name = Joi.string().trim().regex(/^[\sa-zA-Z0-9]{5,30}$/).required();
const password = Joi.string().trim().min(2).max(30).required();
const schema = Joi.object().keys({
  name,
  password,
  confirmPassword: password.label('Confirm password'),
});
const joiOptions = { convert: true, abortEarly: false };
 
const values = { name: 'j', password: 'z', confirmPassword: 'z' };

(1) Convert the Joi messages to the form UI schema, retaining the original message text.

const joiToForms = require('joi-errors-for-forms').form;
const convertToForms = joiToForms();
 
Joi.validate(values, schema, joiOptions, (errs, convertedValues) => {
  console.log(convertToForms(errs));
  // { name: '"name" with value "j" fails to match the required pattern: /^[\\sa-zA-Z0-9]{5,30}$/',
  //   password: '"password" length must be at least 2 characters long',
  //   confirmPassword: '"Confirm password" length must be at least 2 characters long'
  // }
  // or null if no errors.
});

(2) Convert to the form UI schema. Replace Joi messages using Joi error types. (Recommended.)

const joiToForms = require('joi-errors-for-forms').form;
const convertToForms = joiToForms({
  'string.min': () => i18n('"${key}" must be ${limit} or more chars.'),
  'string.regex.base': (context) => {
    switch (context.pattern.toString()) {
      case /^[\sa-zA-Z0-9]{5,30}$/.toString():
        return i18n('"${key}" must consist of letters, digits or spaces.');
    }
  }
});
 
Joi.validate(values, schema, joiOptions, (errs, convertedValues) => {
  console.log(convertToForms(errs));
  // { name: '"name" must consist of letters, digits or spaces.',
  //   password: '"password" must be 2 or more chars.',
  //   confirmPassword: '"Confirm password" must be 2 or more chars.'
  // }
});
 
function i18n(str) { return str; } // internationalization
 

or convert to the Mongoose schema.

const joiToMongoose = require('joi-errors-for-forms').mongoose;
const convertToMongoose = joiToMongoose({
  ... same as above ...
});
 
Joi.validate(values, schema, joiOptions, (errs, convertedValues) => {
  console.log(convertToMongoose(errs));
  // { name: 
  //     { message: '"name" must consist of letters, digits or spaces.',
  //       name: 'ValidatorError',
  //       path: 'name',
  //       type: 'string.regex.base' },
  //   password: 
  //     { message: '"password" must be 2 or more chars.',
  //       name: 'ValidatorError',
  //       path: 'password',
  //       type: 'string.min' },
  //   confirmPassword: 
  //     { message: '"Confirm password" must be 2 or more chars.',
  //       name: 'ValidatorError',
  //       path: 'confirmPassword',
  //       type: 'string.min' }
  // }
});
 

List of substitution tokens. Refer to Joi documentation for more information.

• ${key} prop name, or label if .label('...') was used.
• ${value} prop value. Its rudimentally converted to a string.
• ${pattern} regex value if .regex(...) was involved in the error. Its converted to a string.
• ${limit} allowed length of string.
• ${encoding} string encoding. Could be undefined. Its converted to a string.

Note that type retains the Joi value in the Mongoose schema. It is not converted to what Mongoose would return.

(3) Replace Joi messages with a generic error message.

const convertToForms = joiToForms('"${key}" is badly formed.');
 
Joi.validate(values, schema, joiOptions, (errs, convertedValues) => {
  console.log(convertToForms(errs));
  // { name: '"name" is badly formed.',
  //   password: '"password" is badly formed.',
  //   confirmPassword: '"Confirm password" is badly formed.'
  // }
});
 

(4) Replace Joi messages, by searching for substrings in Joi messages.

const convertToForms = joiToForms([
  { regex: 'at least 2 characters long',
    message: '"${key}" must be 2 or more chars.'
  },
  { regex: /required pattern/,
    message: '"${key}" is badly formed.'
  }
]);
 
Joi.validate(values, schema, joiOptions, (errs, convertedValues) => {
  console.log(convertToForms(errs));
  // { name: '"name" is badly formed.',
  //   password: '"password" must be 2 or more chars.',
  //   confirmPassword: '"Confirm password" must be 2 or more chars.'
  // }
});
 

Motivation

Joi is an enterprise strength schema validator and sanitizer originally developed by Walmart.

The error object it returns, however, usually has to be reformatted for use within web/mobile apps. Its error messages may also have to be converted for internationalization or for clarity.

This package helps with both needs.

Installation

Install Nodejs.

Run npm install joi-errors-for-forms --save in your project folder.

You can then require the package.

// ES5
var joiErrorsToForms = require('joi-errors-for-forms');
var joiToForms = joiErrorsToForms.form;
var joiToMongoose = joiErrorsToForms.mongoose;
// or ES6
import { form as joiToForms, mongoose as joiToMongoose } from 'joi-errors-for-forms';

API Reference

See Code Examples.

Tests

npm test to run tests.

A Note on Internationalization

The options in Joi.validate(value, schema, options, cb)supports a language option with which you can change Joi error messages in bulk.

You can then internationalize your field names and regex descriptions in the schema, e.g.

Joi.string().regex(/^[\sa-zA-Z0-9]$/, i18n('letters, number and spaces')).label(i18n('Confirm password'))

These are suitable methods to internationalize the majority of Joi error messages.

Contributors

• eddyystop

License

MIT. See LICENSE.