RFC8259 describes the JSON data model and interchange format, which is widely used in application-level protocols including RESTful APIs. It is common for applications to request resources via the HTTP POST method, with JSON entities. However, POST is suboptimal for requests which do not modify a resource's state. JSON→URL defines a text format for the JSON data model suitable for use within a URL/URI.

JSON→URL is available as a commonjs module (suitable for use in Node), ES6 module, or a script that may be used directly in a browser.

npm install @jsonurl/jsonurl --save

const JsonURL = require("@jsonurl/jsonurl");

import JsonURL from "@jsonurl/jsonurl";

<script
    src="https://cdn.jsdelivr.net/npm/@jsonurl/jsonurl@1.1.8"
    integrity="sha512-LIJoXzT8Z9ZYDVCop/RciWbhJCDBzOevskMv9YPLHI8kGUtJ32DHHDWdIBLBmMoKkMr7vsZEysOrOBbVg7yioA=="
    crossorigin="anonymous"></script>

Once included, the API is the same for all three.

let value = JsonURL.parse( "(Hello:World!)" );
let string = JsonURL.stringify( value );

If you intend to use JSON→URL inside a browser's address bar then you'll want to enable the AQF (address bar query string friendly) syntax.

let value = JsonURL.parse( "(Hello:Address Bar!!)",  { AQF: true });
let string = JsonURL.stringify( value,  { AQF: true } );

The JSON→URL specification defines the empty composite value, (), because an empty array is indistinguishable from an empty object. This works well in practice, generally, but it can lead to counterintuitive results when parsing JSON→URL text into a language-native object and then stringifying it back into JSON→URL text; the input text doesn't "round-trip" back to itself as expected.

The noEmptyComposite parse option causes the character sequence () to be parsed as an empty array, and the character sequence (:) to be parsed as an empty object. And the noEmptyComposite stringify option instructs stringify to generate those strings appropriately.

let value = JsonURL.parse( "(Array:(true,false,(nested),()),Object:(nested:(:)))",  { AQF: true, noEmptyComposite: true });
let string = JsonURL.stringify( value,  { AQF: true, noEmptyComposite: true });

There are additional options available. The typescript definition file is a good place to learn more.

JSON→URL has no runtime dependencies.

The parser is designed to parse untrusted input. It supports limits on the number of parsed values and depth of nested arrays or objects. When the limit is exceeded an Error is thrown, and reasonable limit values are set by default.