JavaScript try...catch: Catch Parsing Errors and Awaited Rejections

The task

Create one synchronous parse failure and one rejected async operation. Record the two catches and the finally block so their actual ordering can be checked.

Runnable Node 22 example

const assert = require('node:assert/strict');

(async () => {
  const trace = [];
  try { JSON.parse('{bad'); }
  catch (error) { assert(error instanceof SyntaxError); trace.push('parse caught'); }
  try {
    await Promise.reject(new Error('not ready'));
  } catch (error) {
    assert.equal(error.message, 'not ready');
    trace.push('rejection caught');
  } finally { trace.push('cleanup'); }
  assert.deepEqual(trace, ['parse caught', 'rejection caught', 'cleanup']);
  console.log(trace.join(' | '));
})().catch(error => { console.error(error); process.exitCode = 1; });

Expected output and explanation

The JSON operation throws before it returns, so the first catch sees a SyntaxError. Await converts the rejected operation into an exception at the second protected boundary. Its catch checks the known failure and the finally block then records cleanup.

The outer handler makes an unexpected failure in this demonstration visible as a nonzero process result. It does not hide every error under a success message. In application code, distinguish failures you can handle from those you should pass to a higher-level handler.

Pitfall to check

A return or throw inside finally can replace an earlier result or error. Keep cleanup from accidentally masking the event you were trying to report. Likewise, do not leave a started Promise unhandled and assume an unrelated surrounding catch will receive it.