@readme/better-ajv-errors

What is @readme/better-ajv-errors?

@readme/better-ajv-errors is a utility package designed to provide more human-readable error messages when using the AJV JSON schema validator. It enhances the default error messages provided by AJV, making it easier to understand and debug validation issues.

What are @readme/better-ajv-errors's main functionalities?

Human-readable error messages

This feature allows you to generate more readable error messages from AJV validation errors. The code sample demonstrates how to use @readme/better-ajv-errors to enhance the error messages for a simple JSON schema validation.

const Ajv = require('ajv');
const betterAjvErrors = require('@readme/better-ajv-errors');

const ajv = new Ajv();
const schema = {
  type: 'object',
  properties: {
    name: { type: 'string' },
    age: { type: 'integer' }
  },
  required: ['name', 'age']
};

const data = {
  name: 'John Doe',
  age: 'twenty-five'
};

const validate = ajv.compile(schema);
const valid = validate(data);

if (!valid) {
  const output = betterAjvErrors(schema, data, validate.errors, { format: 'js' });
  console.log(output);
}

Other packages similar to @readme/better-ajv-errors

ajv-errors

ajv-errors is a package that allows you to define custom error messages for your JSON schema validations. Unlike @readme/better-ajv-errors, which focuses on making default error messages more readable, ajv-errors lets you specify exactly what the error messages should be.

ajv-i18n

ajv-i18n provides internationalization support for AJV error messages. It translates AJV's default error messages into various languages. While @readme/better-ajv-errors focuses on readability, ajv-i18n focuses on localization.

ajv-keywords

ajv-keywords adds custom validation keywords to AJV, allowing for more complex validation logic. It doesn't directly improve error messages but can be used in conjunction with @readme/better-ajv-errors to provide more detailed validation and error reporting.

README

JSON Schema validation for Human 👨‍🎤

Main goal of this library is to provide relevant error messages like the following:

Differences from better-ajv-errors

• Only targets current Node LTS releases.
• AJV 8 support.
• Default errors stack the error message at the top of the location instead of the bottom.
  • This helps eliminate long blocks of ^^^^^^ pointers.
• Up-to-date dependencies.

Installation

$ npm i better-ajv-errors

Also make sure that you installed ajv package to validate data against JSON schemas.

Usage

First, you need to validate your payload with ajv. If it's invalid then you can pass validate.errors object into better-ajv-errors.

import Ajv from 'ajv';
import betterAjvErrors from 'better-ajv-errors';
// const Ajv = require('ajv');
// const betterAjvErrors = require('better-ajv-errors');

// If you're on anything less than `ajv@7` you need to pass `jsonPointers: true`
const ajv = new Ajv({ jsonPointers: true });

// Load schema and data
const schema = ...;
const data = ...;

const validate = ajv.compile(schema);
const valid = validate(data);

if (!valid) {
  const output = betterAjvErrors(schema, data, validate.errors);
  console.log(output);
}

API

betterAjvErrors(schema, data, errors, [options])

Returns formatted validation error to print in console. See options.format for further details.

schema

Type: Object

The JSON Schema you used for validation with ajv

data

Type: Object

The JSON payload you validate against using ajv

errors

Type: Array

Array of ajv validation errors

options

Type: Object

format

Type: string Default: cli Values: cli js

Use default cli output format if you want to print beautiful validation errors like following:

Or, use js if you are planning to use this with some API. Your output will look like following:

[
  {
    start: { line: 6, column: 15, offset: 70 },
    end: { line: 6, column: 26, offset: 81 },
    error: '/content/0/type should be equal to one of the allowed values: panel, paragraph, ...',
    suggestion: 'Did you mean paragraph?',
  },
];

indent

Type: number null Default: null

If you have an unindented JSON payload and you want the error output indented.

This option have no effect when using the json option.

json

Type: string null Default: null

Raw JSON payload used when formatting codeframe. Gives accurate line and column listings.