README

pretty-print-json

Pretty-print JSON data into HTML to indent and colorize (written in TypeScript)

screenshot

1) Try It Out

Interactive online tool to format JSON:
https://pretty-print-json.js.org

2) Setup

Web browser

Load from the jsdelivr.com CDN:

<link rel=stylesheet href=https://cdn.jsdelivr.net/npm/pretty-print-json@1.2/dist/pretty-print-json.css>
...
<script src=https://cdn.jsdelivr.net/npm/pretty-print-json@1.2/dist/pretty-print-json.min.js></script>

For dark mode, replace pretty-print-json.css with pretty-print-json.dark-mode.css in the <link> tag.

Node.js server

Install package for node:

$ npm install pretty-print-json

Import into your application:

import { prettyPrintJson } from 'pretty-print-json';

Or for older CommonJS/UMD environments:

const { prettyPrintJson } = require('pretty-print-json');  //deprecated

3) Usage

API

const html = prettyPrintJson.toHtml(data, options?);

Example

HTML:

<pre id=account class=json-container></pre>

JavaScript:

Pass data into prettyPrintJson.toHtml() and display the results.

const data = { active: true, mode: '🚃', codes: [48348, 28923, 39080], city: 'London' };
const elem = document.getElementById('account');
elem.innerHTML = prettyPrintJson.toHtml(data);

Options

Name (key)	Type	Default	Description
`indent`	integer	`3`	Number of spaces for indentation.
`lineNumbers`	boolean	`false`	Wrap HTML in an `<ol>` tag to support line numbers.*
`linkUrls`	boolean	`true`	Create anchor tags for URLs.
`quoteKeys`	boolean	`false`	Always double quote key names.

screenshot

*When setting lineNumbers to true, do not use the <pre> tag as the white-space: pre; styling is applied to each line (<li>).

4) TypeScript Declarations

The TypeScript Declaration File file is pretty-print-json.d.ts in the dist folder.

The output of the prettyPrintJson.toHtml(thing: unknown, options?: FormatOptions) function is configured with a FormatOptions object:

type FormatOptions = {
   indent?:      number,   //number of spaces for indentation
   lineNumbers?: boolean,  //add line numbers
   linkUrls?:    boolean,  //create anchor tags for URLs
   quoteKeys?:   boolean,  //always double quote key names
   };

Example TypeScript usage with explicit types:

import { prettyPrintJson, FormatOptions } from 'pretty-print-json';

const data = { active: true, mode: '🚃', codes: [48348, 28923, 39080], city: 'London' };
const options: FormatOptions = { linkUrls: true };
const html: string = prettyPrintJson.toHtml(data, options);

5) Contributor Notes

To be a contributor, fork the project and run the commands npm install and npm test on your local clone. To see some example HTML results, run node spec/examples.js. Make your edits and rerun the tests. Pull requests welcome.

Feel free to submit questions at:
github.com/center-key/pretty-print-json/issues

MIT License | Blog post

Usage no npm install needed!