[EXPERIMENTAL] [WORK IN PROGRESS]

Reference implementation of the fitzJSON semantics interpreter in JavaScript.

Depends on the reference tree-sitter-fitzjson syntax.

Provides fitzJSON.parse and fitzJSON.stringify that work analogous to JSON.parse and JSON.stringify (see below for details).

Install

npm i @xtao-org/fitzjson.js

Use

To use, a parser object must be asynchronously produced first by makeFitzJSON.

import {makeFitzJSON} from '@xtao-org/fitzjson.js'

const fitzJSON = await makeFitzJSON()

const input = `{"a":@bigint 2219302139021039219030213902193}`

const parsed = fitzJSON.parse(input)

const stringified = fitzJSON.stringify(parsed)

console.assert(input === stringified)

fitzJSON.parse and .stringify vs JSON.parse and .stringify

This library provides fitzJSON.parse and fitzJSON.stringify that work analogous to JSON.parse and JSON.stringify.

Aims to support the exact same interface and a superset of the behavior of these functions. For documentation of these, see MDN:

• JSON.stringify
• JSON.parse

The implementations here were written according to these specifications, extending functionality in accordance with the features of fitzJSON.

In particular, in fitzJSON.parse:

• The second argument can be either a reviver function (like in JSON.strigify) OR an options object (unlike JSON.stringify). The options object may contain the reviver function in its reviver property.

Also, in fitzJSON.stringify:

• if a value has a .toFitzJSON method, it will be preferred over .toJSON. The method has the same interface.

• BigInts will be represented as @bigint <numerical value>
• Dates will be represented as @date <ISO string produced by .toISOString()>
• +-Infinity and NaN will be represented literally
• Maps with string keys will be represented the same as objects

• Maps with nonstring keys will cause an error

• a special Decorated class is provided which can be used to put custom decorators in the output. An instance of Decorated will be represented as @<instance decorator> @<instance value>. Such an instance should be constructed with new Decorated(decoratorName, value) where decoratorName should be a valid fitzJSON identifier (pretty much the same as a JavaScript identifier), otherwise the constructor will throw an error. value can be any stringifiable value.

Note: the well-formed JSON.stringify() specification is implemented, so lone UTF-16 surrogates will be properly escaped in the output.