FsConfig doesn't support JSON Array

[Anton Moldovan]

Description

FsConfig doesn't support JSON Array

Repro steps

1. Define config.json
   here is a JSON:
   {
   data: ["1", "2"]
   }

2. Define F# type
   type Config = {
   Data: string list
   }

3. Parse
   let config = ConfigurationBuilder()
   .SetBasePath(Directory.GetCurrentDirectory())
   .AddJsonFile("config.json")
   .Build()
   |> AppConfig

let result = config.Get()

Expected behavior

result should contain not empty Config.Data

Actual behavior

result contains empty Config.Data

• Operating system Windows 10 x64

[Demystify FP]

Hi @AntyaDev,

Can you try with comma separated string instead of the SON array like below?

{
  "data": "1,2"
}

The documention for the list is here https://github.com/demystifyfp/FsConfig#list-type

[Anton Moldovan]

It will not work with complex types.
I mean,
settings: MySettings list

type MySettings = {
}

[Demystify FP]

It is a current limitation. It is due to the fact the list was initially supported for environment variables where we don't have the sophistication of representing a list of a complex type as a string. I am open to a PR or design suggestion if you'd like to contribute.

[Anton Moldovan]

Ah, I see now

FsConfig is a F# library for reading configuration data from environment variables
It's related only for env variables... I just thought FsConfig means - I can parse any config because the name is very general.

[Demystify FP]

@AntyaDev Just to clarify, It supports AppConfig in addition to Env variables with this limitation.