fracturedjson

A Rust port of FracturedJson — a JSON formatter that produces human-readable output with smart line breaks, table-like alignment, and optional comment support.

Overview

FracturedJson formats JSON data in a way that's easy for humans to read while remaining fairly compact. Arrays and objects are written on single lines when they're short and simple enough. When several lines have similar structure, their fields are aligned like a table. Long arrays are written with multiple items per line.

This crate is part of the FracturedJson family:

• Home Page and Browser-based Formatter
• FracturedJson (C#)
• FracturedJsonJs (JavaScript/npm)
• VS Code Extension

Installation

Command-Line Tool

Install the fjson CLI:

cargo install fracturedjson

Library

Add to your Cargo.toml:

[dependencies]
fracturedjson = "0.1"

Command-Line Usage

The fjson command works like jq but focuses on producing beautifully formatted output:

# Format JSON from stdin
echo '{"name":"Alice","scores":[95,87,92]}' | fjson

# Format a file
fjson input.json

# Write to a file
fjson input.json -o output.json

# Minify JSON
fjson --compact < input.json

# Custom formatting
fjson --indent 2 --max-width 80 < input.json

# Handle JSON with comments
fjson --comments preserve < config.jsonc

CLI Options

Run fjson --help for all options.

Library Usage

Reformat JSON Text

use fracturedjson::Formatter;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let input = r#"{"name":"Alice","scores":[95,87,92],"active":true}"#;

    let mut formatter = Formatter::new();
    let output = formatter.reformat(input, 0)?;

    println!("{}", output);
    Ok(())
}

Serialize Rust Values

use fracturedjson::Formatter;
use serde::Serialize;

#[derive(Serialize)]
struct Player {
    name: String,
    scores: Vec<i32>,
    active: bool,
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let player = Player {
        name: "Alice".into(),
        scores: vec![95, 87, 92],
        active: true,
    };

    let mut formatter = Formatter::new();
    let output = formatter.serialize(&player, 0, 100)?;

    println!("{}", output);
    Ok(())
}

Serialize serde_json::Value

use fracturedjson::Formatter;
use serde_json::json;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let value = json!({
        "name": "Alice",
        "scores": [95, 87, 92],
        "active": true
    });

    let mut formatter = Formatter::new();
    let output = formatter.serialize_value(&value, 0, 100)?;

    println!("{}", output);
    Ok(())
}

Minify JSON

use fracturedjson::Formatter;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let input = r#"{
        "name": "Alice",
        "scores": [95, 87, 92]
    }"#;

    let mut formatter = Formatter::new();
    let output = formatter.minify(input)?;

    println!("{}", output);
    // Output: {"name":"Alice","scores":[95,87,92]}
    Ok(())
}

Configuration

Customize formatting behavior via FracturedJsonOptions:

use fracturedjson::{
    Formatter, FracturedJsonOptions, EolStyle,
    NumberListAlignment, CommentPolicy,
};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut formatter = Formatter::new();

    formatter.options.max_total_line_length = 80;
    formatter.options.max_inline_complexity = 1;
    formatter.options.indent_spaces = 2;
    formatter.options.json_eol_style = EolStyle::Lf;
    formatter.options.number_list_alignment = NumberListAlignment::Decimal;

    // Enable comment support (JSON with comments)
    formatter.options.comment_policy = CommentPolicy::Preserve;

    let input = r#"{"values": [1, 2, 3]}"#;
    let output = formatter.reformat(input, 0)?;

    println!("{}", output);
    Ok(())
}

Available Options

Example Output

{
    "BasicObject"   : {
        "ModuleId"   : "armor",
        "Name"       : "",
        "Locations"  : [
            [11,  2], [11,  3], [11,  4], [11,  5], [11,  6], [11,  7], [11,  8], [11,  9],
            [11, 10], [11, 11], [11, 12], [11, 13], [11, 14], [ 1, 14], [ 1, 13], [ 1, 12],
            [ 1, 11], [ 1, 10], [ 1,  9], [ 1,  8], [ 1,  7], [ 1,  6], [ 1,  5], [ 1,  4],
            [ 1,  3], [ 1,  2], [ 4,  2], [ 5,  2], [ 6,  2], [ 7,  2], [ 8,  2], [ 8,  3],
            [ 7,  3], [ 6,  3], [ 5,  3], [ 4,  3], [ 0,  4], [ 0,  5], [ 0,  6], [ 0,  7],
            [ 0,  8], [12,  8], [12,  7], [12,  6], [12,  5], [12,  4]
        ],
        "Orientation": "Fore",
        "Seed"       : 272691529
    },
    "SimilarArrays" : {
        "Katherine": ["blue",       "lightblue", "black"       ],
        "Logan"    : ["yellow",     "blue",      "black", "red"],
        "Erik"     : ["red",        "purple"                   ],
        "Jean"     : ["lightgreen", "yellow",    "black"       ]
    },
    "SimilarObjects": [
        { "type": "turret",    "hp": 400, "loc": {"x": 47, "y":  -4}, "flags": "S"   },
        { "type": "assassin",  "hp":  80, "loc": {"x": 12, "y":   6}, "flags": "Q"   },
        { "type": "berserker", "hp": 150, "loc": {"x":  0, "y":   0}                 },
        { "type": "pittrap",              "loc": {"x": 10, "y": -14}, "flags": "S,I" }
    ]
}

With comment support enabled (CommentPolicy::Preserve):

{
    /*
     * Multi-line comments
     * are fun!
     */
    "NumbersWithHex": [
          254 /*00FE*/,  1450 /*5AA*/,      0 /*0000*/, 36000 /*8CA0*/,    10 /*000A*/,
          199 /*00C7*/, 15001 /*3A99*/,  6540 /*198C*/
    ],
    /* Elements are keen */
    "Elements"      : [
        { /*Carbon*/   "Symbol": "C",  "Number":  6, "Isotopes": [11, 12, 13, 14] },
        { /*Oxygen*/   "Symbol": "O",  "Number":  8, "Isotopes": [16, 18, 17    ] },
        { /*Hydrogen*/ "Symbol": "H",  "Number":  1, "Isotopes": [ 1,  2,  3    ] },
        { /*Iron*/     "Symbol": "Fe", "Number": 26, "Isotopes": [56, 54, 57, 58] }
        // Not a complete list...
    ]
}

License

MIT