# @tduyng/prettyoutput **@tduyng/prettyoutput** is a fast, customizable library for formatting JavaScript/JSON objects into a human-readable, YAML-style output.

## Features - Fast: 2–3x faster than `util.inspect` - Configurable: colors, depth, indentation, etc. - Cross-platform: Node.js, Deno, Bun, and CLI - ESM and CommonJS support - TypeScript-first, with full type safety - Zero dependencies - Tested with high coverage --- Let me know if you want a shorter or more opinionated tone (e.g., for dev-focused landing pages). ## Installation ```bash npm add @tduyng/prettyoutput yarn add @tduyng/prettyoutput pnpm add @tduyng/prettyoutput ``` ## Usage **@tduyng/prettyoutput** is extremely easy to use. Just require it in your project and call the function with your data: ```javascript import { prettyOutput } from '@tduyng/prettyoutput' const data = { username: 'tduyng', url: 'https://github.com/tduyng', projects: ['@tduyng/prettyoutput', '@tduyng/logger'], } console.log(prettyOutput(data)) ``` Sample output: ```bash username: tduyng url: https://github.com/tduyng projects: - @tduyng/prettyoutput - @tduyng/logger ``` Other example: ![Example](docs/images/example.png) ## API `prettyOutput(data, options, indent)` ### Parameters ```md - {\*} data : The JavaScript or JSON object to format - {Object} [options] : Optional. See options below - {number} [indent] : Optional. Indent all output ``` ### Options ```md - {number} [indentationLength] : Length of indentation (in terms of space) - {number} [maxDepth] : maximum sublevel of nested objects/arrays output. Default: 3 - {boolean}[noColor] : disable colors. Default: false - {colors} [colors] : Output colors. See below - {boolean}[alignKeyValues] : Align key values. Default: true - {boolean}[hideUndefined] : Do not display undefined values. Default: false ``` ### Colors Options ```md - {string} [keys] : Objects keys color. Default: green - {string} [dash] : Array prefixing dash ("- "). Default: green - {string} [number] : Numbers color. Default: blue - {string} [string] : Strings color. Default: no color - {string} [true] : Boolean value 'true' color. Default: green - {string} [false] : Boolean value 'false' color. Default: red - {string} [null] : 'Null' color. Default: grey - {string} [undefined] : 'Undefined' color. Default: grey ``` Example using options : ```javascript import { prettyOutput } from '@tduyng/prettyoutput' const data = { username: 'tduyng', url: 'https://github.com/tduyng', projects: ['@tduyng/prettyoutput', '@tduyng/logger'], } const options = { noColor: true, maxDepth: 5, colors: { keys: 'blue', null: 'red', }, } console.log(prettyOutput(data, options, 2)) ``` ## CLI Usage You can also use prettyoutput directly from the command line to format files or standard input. ### Available Aliases There are multiple aliases available for the CLI, allowing you to use the command that best fits your workflow: ```bash # Pretty print a JSON file pretty package.json # for ESM prettyoutput package.json # for ESM pretty-cjs package.json # for CJS prettyoutput-cjs package.json # for CJS ``` Example CLI Output: ![Example](docs/images/cli.png) ### Command Line Options - `--indent`: Set the indentation level (default: 2). - `--depth`: Limit the depth of object printing (default: 3). - `--noColor`: Disable colored output. ```bash # Format with custom indentation, depth, and no color prettyoutput --indent=4 --depth=5 --noColor package.json ``` or ```bash # Indent 4, max depth 5, disable colors cat package.json | prettyoutput --indent=4 --depth=5 --noColor ``` ```bash # Pretty print a JSON file prettyoutput package.json # for ESM pretty package.json # for ESM prettyoutput-cjs package.json # for CJS pretty-cjs package.json # for CJS ``` Example CLI Output: ![Example](docs/images/cli.png) ### Command Line Options - `--indent`: Set the indentation level (default: 2). - `--depth`: Limit the depth of object printing (default: 3). - `--noColor`: Disable colored output. ```bash # Format with custom indentation, depth, and no color prettyoutput --indent=4 --depth=5 --noColor package.json ``` or ```bash # Indent 4, max depth 5, disable colors cat package.json | prettyoutput --indent=4 --depth=5 --noColor ``` ## Benchmark Performance is key for logging, and prettyoutput is built to be fast. Compared to alternatives like `util.inspect` and `prettyjson`, it consistently performs 2x-3x times faster. ### Run Benchmarks ```bash pnpm run benchmark ``` ### Benchmark Results Tested on Node.js 24.8.0 ```bash LEVELS | KEYS | LOOPS | WEIGHTS 1 | 20 | 100 | serializable: 0.9 array: 0.3 object: 0.5 multilineString: 0.3 error: 0.2 NAME | MIN | MAX | MEAN | TOTAL prettyoutput | 6µs 834ns | 2ms 8µs 875ns | 36µs 267ns | 3ms 626µs 709ns prettyjson | 13µs 792ns | 344µs 875ns | 26µs 445ns | 2ms 644µs 583ns util.inspect | 10µs 875ns | 150µs 375ns | 16µs 815ns | 1ms 681µs 588ns @poppinss/dumper | 43µs 209ns | 961µs 959ns | 76µs 326ns | 7ms 632µs 670ns -------------------------------------------------------------------------------------------------------------- LEVELS | KEYS | LOOPS | WEIGHTS 2 | 20 | 100 | serializable: 0.9 array: 0.3 object: 0.5 multilineString: 0.3 error: 0.2 NAME | MIN | MAX | MEAN | TOTAL prettyoutput | 27µs 875ns | 454µs 83ns | 42µs 807ns | 4ms 280µs 793ns prettyjson | 58µs 583ns | 163µs 541ns | 73µs 734ns | 7ms 373µs 456ns util.inspect | 101µs 625ns | 583µs 542ns | 123µs 526ns | 12ms 352µs 668ns @poppinss/dumper | 171µs 458ns | 510µs 250ns | 207µs 106ns | 20ms 710µs 623ns -------------------------------------------------------------------------------------------------------------- LEVELS | KEYS | LOOPS | WEIGHTS 3 | 20 | 100 | serializable: 0.9 array: 0.3 object: 0.5 multilineString: 0.3 error: 0.2 NAME | MIN | MAX | MEAN | TOTAL prettyoutput | 346µs 875ns | 3ms 814µs 709ns | 460µs 657ns | 46ms 65µs 759ns prettyjson | 807µs 750ns | 1ms 256µs 667ns | 899µs 45ns | 89ms 904µs 586ns util.inspect | 1ms 419µs 625ns | 1ms 874µs 375ns | 1ms 532µs 755ns | 153ms 275µs 587ns @poppinss/dumper | 2ms 640µs 584ns | 3ms 596µs 666ns | 2ms 954µs 927ns | 295ms 492µs 722ns -------------------------------------------------------------------------------------------------------------- LEVELS | KEYS | LOOPS | WEIGHTS 4 | 20 | 100 | serializable: 0.9 array: 0.3 object: 0.5 multilineString: 0.3 error: 0.2 NAME | MIN | MAX | MEAN | TOTAL prettyoutput | 3ms 593µs 333ns | 28ms 998µs 208ns | 4ms 444µs 335ns | 444ms 433µs 545ns prettyjson | 6ms 779µs 125ns | 8ms 323µs 292ns | 7ms 344µs 228ns | 734ms 422µs 834ns util.inspect | 13ms 944µs 666ns | 23ms 601µs 458ns | 15ms 140µs 162ns | 1s 514ms 16µs 206ns @poppinss/dumper | 31ms 645µs 458ns | 44ms 678µs 500ns | 35ms 198µs 832ns | 3s 519ms 883µs 256ns -------------------------------------------------------------------------------------------------------------- LEVELS | KEYS | LOOPS | WEIGHTS 4 | 20 | 200 | serializable: 0.9 array: 0.3 object: 0.5 multilineString: 0.3 error: 0.2 NAME | MIN | MAX | MEAN | TOTAL prettyoutput | 2ms 472µs 375ns | 19ms 756µs 416ns | 2ms 841µs 423ns | 568ms 284µs 792ns prettyjson | 3ms 983µs 584ns | 5ms 516µs 375ns | 4ms 419µs 219ns | 883ms 843µs 868ns util.inspect | 14ms 861µs 417ns | 23ms 170µs 792ns | 16ms 48µs 375ns | 3s 209ms 675µs 126ns @poppinss/dumper | 20ms 774µs 625ns | 28ms 990µs 41ns | 23ms 617µs 484ns | 4s 723ms 496µs 967ns -------------------------------------------------------------------------------------------------------------- LEVELS | KEYS | LOOPS | WEIGHTS 5 | 10 | 100 | serializable: 0.9 array: 0.3 object: 0.5 multilineString: 0.3 error: 0.2 NAME | MIN | MAX | MEAN | TOTAL prettyoutput | 540µs 542ns | 3ms 999µs 667ns | 644µs 326ns | 64ms 432µs 622ns prettyjson | 968µs 0ns | 1ms 804µs 625ns | 1ms 105µs 952ns | 110ms 595µs 295ns util.inspect | 2ms 859µs 959ns | 3ms 856µs 541ns | 3ms 128µs 76ns | 312ms 807µs 666ns @poppinss/dumper | 4ms 281µs 167ns | 5ms 567µs 291ns | 4ms 708µs 354ns | 470ms 835µs 455ns -------------------------------------------------------------------------------------------------------------- ``` For detailed benchmark results, refer to the [benchmark documentation](./benchmark/README.md). ## Testing Clone the repository and install development dependencies: ```bash pnpm install ``` Run tests: ```bash pnpm run test # or pnpm run coverage ``` ## Contribution If you'd like to contribute to this project, feel free to submit issues and pull requests. Contributions are always welcome! ## Credits **@tduyng/prettyoutput** is based on the original [prettyoutput](https://github.com/keepitcool/prettyoutput) project, which is now archived. Special thanks to [@bnadim](https://github.com/bnadim) for creating the original project, and to all contributors who helped enhance it over time.