deserialize.rs

use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize, Debug)]
#[serde(untagged)]
enum Stuff {
    Array(Vec<u8>),
    Number(u8),
}

#[derive(Serialize, Deserialize, Debug)]
struct Object {
    name: String,
    stuff: Stuff,
}

fn main() {
    let objs: Vec<Object> = serde_json::from_str(&include_str!("../objects.json")).unwrap();

    println!("{:?}", objs);
    // output:
    //[Object { name: "quack", stuff: Array([1, 2, 3]) }, Object { name: "quack2", stuff: Number(50) }]
}

objects.json

[
    {
        "name": "quack",
        "stuff": [
            1,
            2,
            3
        ]
    },
    {
        "name": "quack2",
        "stuff": 50
    }
]