deno install -Afq -n deno_bindgen https://deno.land/x/deno_bindgen/cli.ts

# Cargo.toml
[dependencies]
deno_bindgen = "0.2"
serde = { version = "1", features = ["derive"] }

// add.rs
use deno_bindgen::deno_bindgen;

#[deno_bindgen]
pub struct Input {
  a: i32,
  b: i32,
}

#[deno_bindgen]
fn add(input: Input) -> i32 {
  input.a + input.b
}

$ deno_bindgen

// add.ts
import { add } from "./bindings/bindings.ts";

add({ a: 1, b: 2 }); // 3