json5 vs hjson
JSON Parsing and Serialization Comparison
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What's JSON Parsing and Serialization?

hjson and json5 are libraries that extend the JSON format to make it more human-friendly while remaining compatible with JavaScript. They allow for more flexible syntax, such as comments, unquoted keys, and trailing commas, which can make configuration files and data structures easier to read and write. hjson focuses on providing a more readable format with features like multi-line strings and better handling of whitespace, while json5 aims to enhance JSON with a minimal set of changes to improve its usability without sacrificing compatibility.

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json583,977,6226,743235 kB34-MIT
hjson256,889418-234 years agoMIT
Feature Comparison: json5 vs hjson

Readability

  • json5:

    json5 enhances readability by allowing unquoted keys, trailing commas, and comments (though comments are not supported in all parsers). These features make JSON5 files easier to edit while still being relatively close to standard JSON.

  • hjson:

    hjson significantly improves readability by allowing comments, multi-line strings, and a more relaxed syntax that reduces the need for quotes and braces. This makes it easier for humans to write and understand configuration files.

Compatibility

  • json5:

    json5 is designed to be compatible with existing JSON parsers, with the main exception being that not all parsers support its additional features (like unquoted keys and trailing commas). This makes JSON5 a good choice for projects that need to integrate with standard JSON while benefiting from its enhancements.

  • hjson:

    hjson is not fully compatible with standard JSON due to its relaxed syntax and additional features. However, it provides a parser that can convert HJSON back to JSON, making it suitable for applications that can handle the conversion.

Comment Support

  • json5:

    json5 also supports comments, including single-line (//) and multi-line (/* ... */) comments. This feature helps improve the clarity of JSON5 files, especially in complex structures.

  • hjson:

    hjson fully supports comments, allowing developers to add explanations and notes directly within the data. This is particularly useful for configuration files where context may be needed.

Multi-line Strings

  • json5:

    json5 does not have built-in support for multi-line strings, but it allows for them using standard JavaScript string syntax (e.g., using backticks for template literals). However, this is not as seamless as HJSON's multi-line string support.

  • hjson:

    hjson supports multi-line strings natively, allowing for more natural representation of text blocks without the need for escape characters. This feature is especially useful for storing large text data or documentation within the file.

Example Code

  • json5:

    Example of JSON5 with comments and unquoted keys:

    {
  // This is a comment
  unquotedKey: "value",
  trailingComma: "value",
  list: [1, 2, 3,], // Trailing comma
}
  • hjson:

    Example of HJSON with comments and multi-line strings:

    {
  // This is a comment
  key: "value",  // Inline comment
  multiLine: "This is a multi-line string\
  that spans multiple lines.",
  list: [1, 2, 3],
}
How to Choose: json5 vs hjson
  • json5:

    Choose json5 if you need a lightweight solution that adds a few simple features to JSON, such as unquoted keys and trailing commas, while maintaining a focus on compatibility with existing JSON parsers. It is ideal for projects that require a minimalistic approach to enhancing JSON.

  • hjson:

    Choose hjson if you prioritize readability and want a format that allows for comments, multi-line strings, and more relaxed syntax. It is particularly useful for configuration files where human editing is common.

Similar Npm Packages to json5

json5 is a JavaScript library that extends JSON (JavaScript Object Notation) to allow for a more human-friendly syntax. It enables developers to write JSON-like data structures with additional features such as comments, unquoted keys, and trailing commas. This makes it easier to read and write configuration files or data structures without the strict syntax rules of standard JSON. By using json5, developers can create more maintainable and understandable data representations, especially in scenarios where configuration files are frequently edited.

While json5 offers a flexible approach to data representation, there are alternatives that also aim to improve upon standard JSON. One notable alternative is hjson. Hjson is a user-friendly alternative to JSON that allows for a more relaxed syntax, making it easier to read and write. It supports features like comments, multi-line strings, and more intuitive formatting options. Hjson is particularly useful for configuration files and data interchange where human readability is a priority.

For a detailed comparison between json5 and hjson, you can visit: Comparing hjson vs json5.

Similar Npm Packages to hjson

hjson is a human-friendly JSON format that aims to make JSON more readable and writable for humans. It allows for comments, flexible syntax, and a more relaxed structure compared to standard JSON, making it easier to work with, especially for configuration files. Hjson is particularly useful in scenarios where configuration files need to be edited by non-developers or when readability is a priority.

While Hjson provides a unique approach to data serialization, there are several alternatives that also offer human-readable formats. Here are a few notable options:

  • json5 is an extension of JSON that allows for a more flexible syntax, including comments, trailing commas, and unquoted property names. It is designed to be a superset of JSON, making it easy to parse JSON5 data using existing JSON parsers. If you need a format that retains the structure of JSON while allowing for more human-friendly features, JSON5 is an excellent choice.
  • toml is a configuration file format that is designed to be easy to read due to its clear semantics. It uses a simple key-value pair structure and supports nested tables, arrays, and comments. TOML is often favored for configuration files in projects where clarity and simplicity are paramount. If you are looking for a format that is both human-readable and easy to parse, TOML is a strong candidate.
  • yaml (YAML Ain't Markup Language) is a human-readable data serialization format that is often used for configuration files and data exchange between languages. YAML supports complex data structures, including lists and dictionaries, and allows for comments, making it a versatile choice for many applications. If you need a format that can handle complex data structures while remaining readable, YAML is a popular and powerful option.

To explore how Hjson compares with JSON5, TOML, and YAML, check out the comparison: Comparing hjson vs json5 vs toml vs yaml.

README for json5

JSON5 – JSON for Humans

Build Status Coverage Status

JSON5 is an extension to the popular JSON file format that aims to be easier to write and maintain by hand (e.g. for config files). It is not intended to be used for machine-to-machine communication. (Keep using JSON or other file formats for that. 🙂)

JSON5 was started in 2012, and as of 2022, now gets >65M downloads/week, ranks in the top 0.1% of the most depended-upon packages on npm, and has been adopted by major projects like Chromium, Next.js, Babel, Retool, WebStorm, and more. It's also natively supported on Apple platforms like MacOS and iOS.

Formally, the JSON5 Data Interchange Format is a superset of JSON (so valid JSON files will always be valid JSON5 files) that expands its syntax to include some productions from ECMAScript 5.1 (ES5). It's also a strict subset of ES5, so valid JSON5 files will always be valid ES5.

This JavaScript library is a reference implementation for JSON5 parsing and serialization, and is directly used in many of the popular projects mentioned above (where e.g. extreme performance isn't necessary), but others have created many other libraries across many other platforms.

Summary of Features

The following ECMAScript 5.1 features, which are not supported in JSON, have been extended to JSON5.

Objects

  • Object keys may be an ECMAScript 5.1 IdentifierName.
  • Objects may have a single trailing comma.

Arrays

  • Arrays may have a single trailing comma.

Strings

  • Strings may be single quoted.
  • Strings may span multiple lines by escaping new line characters.
  • Strings may include character escapes.

Numbers

  • Numbers may be hexadecimal.
  • Numbers may have a leading or trailing decimal point.
  • Numbers may be IEEE 754 positive infinity, negative infinity, and NaN.
  • Numbers may begin with an explicit plus sign.

Comments

  • Single and multi-line comments are allowed.

White Space

  • Additional white space characters are allowed.

Example

Kitchen-sink example:

{
  // comments
  unquoted: 'and you can quote me on that',
  singleQuotes: 'I can use "double quotes" here',
  lineBreaks: "Look, Mom! \
No \\n's!",
  hexadecimal: 0xdecaf,
  leadingDecimalPoint: .8675309, andTrailing: 8675309.,
  positiveSign: +1,
  trailingComma: 'in objects', andIn: ['arrays',],
  "backwardsCompatible": "with JSON",
}

A more real-world example is this config file from the Chromium/Blink project.

Specification

For a detailed explanation of the JSON5 format, please read the official specification.

Installation and Usage

Node.js

npm install json5

CommonJS

const JSON5 = require('json5')

Modules

import JSON5 from 'json5'

Browsers

UMD

<!-- This will create a global `JSON5` variable. -->
<script src="https://unpkg.com/json5@2/dist/index.min.js"></script>

Modules

<script type="module">
  import JSON5 from 'https://unpkg.com/json5@2/dist/index.min.mjs'
</script>

API

The JSON5 API is compatible with the JSON API.

JSON5.parse()

Parses a JSON5 string, constructing the JavaScript value or object described by the string. An optional reviver function can be provided to perform a transformation on the resulting object before it is returned.

Syntax

JSON5.parse(text[, reviver])

Parameters

  • text: The string to parse as JSON5.
  • reviver: If a function, this prescribes how the value originally produced by parsing is transformed, before being returned.

Return value

The object corresponding to the given JSON5 text.

JSON5.stringify()

Converts a JavaScript value to a JSON5 string, optionally replacing values if a replacer function is specified, or optionally including only the specified properties if a replacer array is specified.

Syntax

JSON5.stringify(value[, replacer[, space]])
JSON5.stringify(value[, options])

Parameters

  • value: The value to convert to a JSON5 string.
  • replacer: A function that alters the behavior of the stringification process, or an array of String and Number objects that serve as a whitelist for selecting/filtering the properties of the value object to be included in the JSON5 string. If this value is null or not provided, all properties of the object are included in the resulting JSON5 string.
  • space: A String or Number object that's used to insert white space into the output JSON5 string for readability purposes. If this is a Number, it indicates the number of space characters to use as white space; this number is capped at 10 (if it is greater, the value is just 10). Values less than 1 indicate that no space should be used. If this is a String, the string (or the first 10 characters of the string, if it's longer than that) is used as white space. If this parameter is not provided (or is null), no white space is used. If white space is used, trailing commas will be used in objects and arrays.
  • options: An object with the following properties:
    • replacer: Same as the replacer parameter.
    • space: Same as the space parameter.
    • quote: A String representing the quote character to use when serializing strings.

Return value

A JSON5 string representing the value.

Node.js require() JSON5 files

When using Node.js, you can require() JSON5 files by adding the following statement.

require('json5/lib/register')

Then you can load a JSON5 file with a Node.js require() statement. For example:

const config = require('./config.json5')

CLI

Since JSON is more widely used than JSON5, this package includes a CLI for converting JSON5 to JSON and for validating the syntax of JSON5 documents.

Installation

npm install --global json5

Usage

json5 [options] <file>

If <file> is not provided, then STDIN is used.

Options:

  • -s, --space: The number of spaces to indent or t for tabs
  • -o, --out-file [file]: Output to the specified file, otherwise STDOUT
  • -v, --validate: Validate JSON5 but do not output JSON
  • -V, --version: Output the version number
  • -h, --help: Output usage information

Contributing

Development

git clone https://github.com/json5/json5
cd json5
npm install

When contributing code, please write relevant tests and run npm test and npm run lint before submitting pull requests. Please use an editor that supports EditorConfig.

Issues

To report bugs or request features regarding the JSON5 data format, please submit an issue to the official specification repository.

Note that we will never add any features that make JSON5 incompatible with ES5; that compatibility is a fundamental premise of JSON5.

To report bugs or request features regarding this JavaScript implementation of JSON5, please submit an issue to this repository.

Security Vulnerabilities and Disclosures

To report a security vulnerability, please follow the follow the guidelines described in our security policy.

License

MIT. See LICENSE.md for details.

Credits

Aseem Kishore founded this project. He wrote a blog post about the journey and lessons learned 10 years in.

Michael Bolin independently arrived at and published some of these same ideas with awesome explanations and detail. Recommended reading: Suggested Improvements to JSON

Douglas Crockford of course designed and built JSON, but his state machine diagrams on the JSON website, as cheesy as it may sound, gave us motivation and confidence that building a new parser to implement these ideas was within reach! The original implementation of JSON5 was also modeled directly off of Doug’s open-source json_parse.js parser. We’re grateful for that clean and well-documented code.

Max Nanasy has been an early and prolific supporter, contributing multiple patches and ideas.

Andrew Eisenberg contributed the original stringify method.

Jordan Tucker has aligned JSON5 more closely with ES5, wrote the official JSON5 specification, completely rewrote the codebase from the ground up, and is actively maintaining this project.

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