README.md

FSharp.Data.Mutator

Enables to create copies (similar to lenses) to generated FSharp.Data types (json only for now), The library now depends both on FSharp.Data and Newtonsoft.Json as dependencies, but can be improved.

A medium article about it.

Usage

#r "nuget:FSharp.Data.Mutator,0.1.0-beta"

open FSharp.Data
open FSharp.Data.Mutator

[<Literal>]
let jsonTest =
    """
    {
        "name":"hey",
        "nested": {
            "another" : "val"
        },
        "items" : [
            { "first" : 1 }
        ] 
    }
    """

type TestJsonProvided = JsonProvider<jsonTest>

TestJsonProvided.GetSample().Change(fun x -> x.Name = "bye")

Or for a chain of calls (more functional-way)

TestJsonProvided.GetSample()
|> Change <@ fun x -> x.Name = "one" @>
|> Change <@ fun x -> x.Nested.Another = "two" @>
|> Change <@ fun x -> x.Items.[0].First = 500 @>

and the output should be

val it : JsonProvider<...>.Root =
  {
  "name": "one",
  "nested": {
    "another": "two"
  },
  "items": [
    {
      "first": 500
    }
  ]
}

Have fun!