This page is for the current stable release of Schemars (v0.8.x).

To view this page for the v1 version of Schemars, which is still under development, click here.

Serialize Enum as Number (serde_repr Compatibility)

If you use the #[repr(...)] attribute on an enum to give it a C-like representation, then you may also want to use the serde_repr crate to serialize the enum values as numbers. In this case, you should use the corresponding JsonSchema_repr derive to ensure the schema for your type reflects how serde formats your type.

use schemars::{schema_for, JsonSchema_repr};

#[derive(JsonSchema_repr)]
#[repr(u8)]
enum SmallPrime {
    Two = 2,
    Three = 3,
    Five = 5,
    Seven = 7,
}

fn main() {
    let schema = schema_for!(SmallPrime);
    println!("{}", serde_json::to_string_pretty(&schema).unwrap());
}

Click to see the output JSON schema...

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "SmallPrime",
  "type": "integer",
  "enum": [
    2,
    3,
    5,
    7
  ]
}