Send enter key to child_process using streams

Question

I am trying to send Enter key to a child_process in Node.js. \r\n, \n, isn't actually sending the Enter key to a Psy Shell (a PHP repl).

const execa = require("execa");
const { Readable } = require("stream");

const subprocess = execa("php", ["artisan", "tinker"], { cwd: "C:\\laravel-app" });

const str = Readable.from("5+5;\r\n2+2;"); // <-- Here
str.pipe(subprocess.stdin);

(async () => {
  const a = await readableToString(subprocess.stdout);
  const b = await readableToString(subprocess.stderr);
  subprocess.kill();
  console.log(a);
  console.log(b);
})();

// This function turns a stream to a readable string
async function readableToString(readable) {
  let result = "";
  for await (const chunk of readable) {
    result += chunk;
  }
  return result;
}

The output should be

10
4

Instead I'm getting

4

It's the same result I get when I input 5+5;2+2 in PsySh (in the terminal manually).