One can use the await keyword outside of async functions with Top-level await and the happy news is you can use it today in Node and REPL.

As of today, if we execute the below piece of code in node env:

await Promise.resolve(42);

We would see a: SyntaxError: await is only valid in async function

So, we would normally mitigate this by wrapping it in an async function:

(async function() {
  const answer = await Promise.resolve(42);
  // answer would be 42
}());

But with top level await it gets easier - we could just do const answer = await Promise.resolve(42); Note that this will only work at the top level of modules only.

Node.js v14.3.0+ Support

Node.js v14.3.0 was released with the support of top-level await! But we always had a flag to enable top-level await on the REPL, ever since node v10!

The --experimental-repl-await enables experimental top-level await keyword support in REPL, so all you have to do is start the REPL with the flag node --experimental-repl-await and that’s it.

Usage in Scripts

// home.mjs
export function home() {
  return 'Hello home!';
}

// index.mjs
const home = await import('./home.mjs');
console.log(home());

You could execute this using node --experimental-top-level-await.

TL;DR: For REPL we would need --experimental-repl-await and for .mjs scripts --experimental-top-level-await as of today.