Validate only if one property equals to a value

[CarterLi]

I'm creating JSON schema for the JSON configuration file of my project

This is the WIP schema: https://github.com/fastfetch-cli/fastfetch/blob/dev/src/data/json_schema.jsonc

---

The question:

My program have many modules. Each module have its own type. eg

[
    {
        "type": "CPU",
        "temp": true
    },
    {
        "type": "GPU",
        "temp": true
    },
    {
        "type": "LocalIp",
        "showIpv6": true,
        "namePrefix": "en0"
    }
]

"type" specifies the module type. This is the only required property.

Only if the module type is either "CPU" or "GPU", a user can specify another property "temp". Only if the module type is "LocalIp", a user can specify another two properties "showIpv6" and "namePrefix". Module CPU and GPU cannot have property showIpv6 and namePrefix. Module LocalIp cannot have property temp.

What's the best way to do that?

[jdesrosiers]

Since this is for a config file, I assume the intended validator is your editor/IDE of choice. Unfortunately, a lot of editors/IDEs haven't implemented some of the newer JSON Schema features (specifically, unevaluatedProperties) that would be useful in cases like this. Therefore, I'd suggest something like the following.

{
  "anyOf": [
    {
      "type": "object",
      "properties": {
        "type": { "enum": ["CPU", "GPU"] },
        "temp": { "type": "boolean" }
      },
      "required": ["type"],
      "additionalProperties": false
    },
    {
      "type": "object",
      "properties": {
        "type": { "const": "LocalIp" },
        "showIpv6": { "type": "boolean" },
        "namePrefix": { "type": "string" }
      },
      "required": ["type"],
      "additionalProperties": false
    }
  ]
}

In most validators, you won't get very good error messages with this pattern in some cases, but editors/IDEs tend to handle this kind of thing pretty well, so I think this will be a good approach for you.

[CarterLi]

Completely the same as what I did 😄

[CarterLi]

Another question

Can I make enums / constants case insensitive?

[jdesrosiers]

Unfortunately, there isn't a good solution for that. I think the best you can do is to use regular expressions something like this.

{
  "$defs": {
    "my-enum": {
      "anyOf": [
        { "type": "string", "pattern": "^[fF][oO][oO]$" },
        { "type": "string", "pattern": "^[bB][aA][rR]$" }
      ]
    }
  }
}