Rust AnyMap

anymap.rs

use std::any::{Any, TypeId};
use std::collections::HashMap;

#[derive(Default)]
pub struct AnyMap {
    map: HashMap<TypeId, Box<dyn Any>>,
}

impl AnyMap {
    pub fn insert<T: 'static>(&mut self, t: T) {
        self.map.insert(TypeId::of::<T>(), Box::new(t));
    }
    
    pub fn get<T: 'static>(&self) -> Option<&T> {
        self.map
            .get(&TypeId::of::<T>())
            .and_then(|value| value.downcast_ref())
    }
}

#[test]
fn test() {
    let mut map = AnyMap::default();
    map.insert("lol");
    map.insert(5 as usize);
    
    assert_eq!(Some(&"lol"), map.get::<&str>());
    assert_eq!(Some(&5), map.get::<usize>());
    assert_eq!(None, map.get::<u8>());
}