How to run a CMD on web assembly without a server

Question

I wanted to create a web assembly program that would enable me to execute bash commands and get output without contacting a server.

I created some rust code and did a wasm-pack compiling but it gives this error

RuntimeError: unreachable executed

My code

use std::process::Output;
use wasm_bindgen::prelude::*;
use std::process::Command;

#[wasm_bindgen]
pub fn exec(code:&str)->Vec<u8>{
    
    let output = if cfg!(target_os = "windows") {
    Command::new("cmd")
            .args(["/C", code])
            .output()
            .expect("failed to execute process")
    } else {
        Command::new("sh")
                .arg("-c")
                .arg(code)
                .output()
                .expect("failed to execute process")

    };

    output.stdout
}

^^lib.rs (used wasm-pack)

RuntimeError: unreachable executed