json5

json5 is a library for serializing and deserializing JSON5, a superset of JSON.

This library is a fork of Samson library.

Installation

nimble install json5

Usage

The main API consists of only two procs: toJson5 and fromJson5.

Simple example

import json5

type User = object
    name: string
    age: range[0..high(int)]
    timezone: Option[string]

let input = """
[
    {"name": "John Doe", age: 25},
    {"name": "Jane Doe", age: 22, timezone: "Europe/Stockholm"}
]
"""

let parsed = fromJson5(input, seq[User])
echo parsed
# => @[(name: "John Doe", age: 25, timezone: None[string]), (name: "Jane Doe", age: 22, timezone: Some("Europe/Stockholm"))]
echo toJson5(parsed)
# => [{"name": "John Doe", age: 25, timezone: null}, {"name": "Jane Doe", age: 22, timezone: "Europe/Stockholm"}]

Advanced example

Pragma annotations can be used to control how an object type is serialized and deserialized. These are defined and documented in the json5 / pragmas module.

import std/times, json5, json5/pragmas

type Advanced = object
    nimField {.jsonFieldName: "jsonField".}: int
    hidden {.jsonExclude.}: int
    date {.jsonDateTimeFormat: "yyyy-MM-dd".}: DateTime

let x = Advanced(
    nimField: 1,
    hidden: 2,
    date: initDateTime(1, mJan, 2010, 12, 00, 00, utc())
)
echo toJson5(x)
# => {"jsonField": 1, date: "2010-01-01"}

Supported types

The following types in the standard library have special support in Json5:

int8, int16, int32, int, and int64
uint8, uint16, and uint32 (note: uint and uint64 are not supported for now)
float32 and float64
string
char
enum
seq
array
bool
range (with range checking)
options.Option (maps to null when empty)
times.Time
times.DateTime
tables.Table and tables.OrderedTable (maps to object)
set, sets.HashSet, and sets.OrderedSet

Json5 also supports custom object (mapped to objects in JSON5) and tuple (mapped to arrays in JSON5) types.

Generated docs

Planned features

Stream based API.
Support for type variants.
Support for pretty printing.
Support for dynamic JSON.
A strict JSON mode which doesn't support JSON5 features.

denull/json5