jsonlint

What is jsonlint?

jsonlint is a JSON parser and validator. It helps in validating JSON data, ensuring that it is correctly formatted and adheres to JSON standards. It can also pretty-print JSON data, making it easier to read and debug.

What are jsonlint's main functionalities?

Validate JSON

This feature allows you to validate a JSON string. If the JSON is valid, it will print 'Valid JSON'. If the JSON is invalid, it will catch the error and print 'Invalid JSON' along with the error details.

const jsonlint = require('jsonlint');
const jsonString = '{ "name": "John", "age": 30 }';
try {
  jsonlint.parse(jsonString);
  console.log('Valid JSON');
} catch (e) {
  console.error('Invalid JSON', e);
}

Pretty Print JSON

This feature allows you to pretty-print a JSON string. It parses the JSON and then uses JSON.stringify to format it with indentation, making it easier to read.

const jsonlint = require('jsonlint');
const jsonString = '{ "name": "John", "age": 30 }';
try {
  const parsed = jsonlint.parse(jsonString);
  const pretty = JSON.stringify(parsed, null, 2);
  console.log(pretty);
} catch (e) {
  console.error('Invalid JSON', e);
}

Other packages similar to jsonlint

ajv

Ajv is a JSON schema validator. It is used to validate JSON data against a JSON schema, ensuring that the data adheres to a predefined structure. Unlike jsonlint, which focuses on basic JSON validation, Ajv provides more advanced validation capabilities using JSON schemas.

jsonschema

jsonschema is another JSON schema validator. It validates JSON data against a schema and provides detailed error messages. It is similar to Ajv but may have different performance characteristics and API design.

joi

Joi is a powerful schema description language and data validator for JavaScript objects. It is not limited to JSON and can be used to validate any JavaScript object. It provides a rich set of validation rules and is highly customizable.

README

JSON Lint

A pure JavaScript version of the service provided at jsonlin.com.

Command line interface

Install jsonlint with npm to use the command line interface:

npm install jsonlint -g

Validate a file like so:

jsonlint myfile.json

or pipe input into stdin:

cat myfile.json | jsonlint

jsonlint will either report a syntax error with details or pretty print the source if it is valid.

Options

$ jsonlint -h
Usage: jsonlint <file> [options]

<file>		file to parse; otherwise uses stdin

options:
-v, --version		print version and exit
-s, --sort-keys		sort object keys
-i, --in-place		overwrite the file
-t CHAR, --indent CHAR		character(s) to use for indentation

Module interface

I'm not sure why you wouldn't use the built in JSON.parse but you can use jsonlint from a CommonJS module:

var jsonlint = require("jsonlint");

jsonlint.parse('{"creative?": false}');

It returns the parsed object or throws an Error.