Parse JSON Data

Nanyx provides a json module for encoding and decoding JSON.

Setup

nanyx new json_parsing
cd json_parsing
nanyx install nanyx.web

module main

import nanyx.web/json

type User = (name: string, age: int)

def decodeUser: string -> Result(User, DecodeError) = { data ->
  data
    \json.decode(json.record(
      name = json.field("name", json.string)
      age = json.field("age", json.int)
    ))
}

@entry
def main = {
  -- A single-quoted string is raw, so the braces are not interpolated
  def data = '{"name": "Alice", "age": 30}'

  match decodeUser(data)
    | #some(user) -> println("Hello, {user.name}!")
    | #error(_) -> println("Invalid JSON")
}

Encoding JSON

def jsonString =
  json.object([
    ("name", json.string("Alice"))
    ("age", json.int(30))
    ("active", json.bool(true))
  ])
  \json.toString

-- {"name":"Alice","age":30,"active":true}

Working with arrays

def usersJson = 
  users \map { user ->
    json.object([
      ("name", json.string(user.name))
      ("age", json.int(user.age))
    ])
  }
  \json.array
  \json.toString