Extended JSON(ESON)

JSON is great for sharing data in a human readable format but sometimes it lacks in object types support. ESON does not re-invent the wheel, it just provides a base for you to implement extended JSON objects allowing you to share data between services, apps and languages as objects.

ESON comes with built in extensions for date and datetime. You can write your own extensions to manage custom data.

This is the javascript version of ESON. See other languages here

Getting Started

Note: Javascript doesn't support date and datetime as separate entities. It can decode date and datetime objects but it encodes datetime even for what was originally an ESON date object.

Note: EsonDatetime objects in Javascript are not timezone aware.

ESON is safe to use in browser, webworkers and in node-js.

Install

Run npm install eson-js Yarners yarn add eson-js

Usage

Below is a summary of various operations using eson. Click here to open a live test environment.

Encoding:

import eson from "eson-js"

const user = {
    name: "Jane Doe",
    date_of_birth: date.today(),
    registered: datetime.now()
}

// Encoding the data (True argument to make it pretty. Not required)
const eson_data = eson.encode(user, True)
console.log(eson_data)

// Sample output
/*
{
    "name": "Jane Doe",
    "EsonDate~date_of_birth": {"year": 2020, "month": 04, "day": 10},
    "EsonDatetime~registered": {...}
}
*/

Decoding

import eson from "eson-js"

const eson_data = '{"EsonDatetime~datetime": {"timestamp": 1588822240000400}, "array": ["Some string",0,{"EsonDatetime~":{"timestamp":1588822240400000}},false,null]}'
const data = eson.decode(eson_data)

console.log(data)

Extending ESON

You can extend ESON to achieve various purposes, e.g loading a database entity when you recieve it's ID

An extension should have the keys should_encode, encode, decode and name. Below is the sample code used to extend Datetime objects in ESON

import eson from "eson-js"

exports.EsonDatetime = {
    name: "EsonDatetime",
    should_encode: value => value instanceof Date,
    encode: value => {
        // ESON processes datetime in micro-seconds
        return {
            timestamp: value.getTime() * 1000,
        }
    },
    decode: value => new Date(value.timestamp / 1000),
}

Once an extension is created, at the entry of your application add the extension to ESON

import eson from "eson-js"

eson.add_extension(EsonDatetime)

That's it, your extension is ready to encode objects.