javascriptnode.jslibsodium

Javascript is not returning objects as expected

Javascript (or Node.js) is not returning objects as expected.

The following code logs an empty array.

const _sodium = require('libsodium-wrappers');

const sodium = (async () => {
  await _sodium.ready;
  return _sodium;
})();

console.log(Object.getOwnPropertyNames(sodium));

On the other hand, the following code works as expected.

const _sodium = require('libsodium-wrappers');

(async () => {
  await _sodium.ready;
  const sodium = _sodium;
  console.log(Object.getOwnPropertyNames(sodium));
})();

In the first code snippet, it seems like the sodium object is tied to its lexical environment, which would explain why an empty array is printed. I would be interested in what's going on here (including an explanation of what's going on under the hood). Thanks.

Solution

  • It's not about lexical context.

    You just not awaiting for ready in the first example.

    First example simplified:

    (async() => {
  console.log('start')
  await new Promise(r => setTimeout(r, 3000))
  console.log('finish')
})()

    Second example simplified:

    console.log('start');
(async() => {
  await new Promise(r => setTimeout(r, 3000))
})();
console.log('finish')