AggregateError

One of the big themes of the web these days is concurrency, which leads to accomplishing tasks asynchronously. In doing so, the possibility of multiple errors can occur. Instead of providing a generic error, optimally you’d provide a wealth of error information. TheAggregateError error lets developers throw multiple errors within one single Error. Let’s see how it works.

To throw a single error that represents multiple errors, let’s employ AggregateError:

const error = new AggregateError([
  new Error('ERROR_11112'),
  new TypeError('First name must be a string'),
  new RangeError('Transaction value must be at least 1'),
  new URIError('User profile link must be https'),
], 'Transaction cannot be processed')

Throwing an AggregateError gets you the following information:

error instanceof AggregateError // true
error.name // 'AggregateError'
error.message // 'Transaction cannot be processed'
error.errors // The array of errors

The AggregateError is incredibly useful when validating multiple sets of data; instead of throwing one error at a time, grouping them into one is ideal! AggregateError would be really useful in a Promise.any situation. Communicative, information-rich errors FTW!