Sort mongo results by string enum value

Question

Is there any way to sort documents from MongoDB based on an enumeration of string values?

What I'm trying to achieve is simply sorting log message objects based on a severity. So the documents look like:

{message: 'An error', severity: 'error'}
{message: 'A warning', severity: 'warning'}
{message: 'Informational message', severity: 'info'}

And I'd like the results sorted by the logical severity (e.g. error->warning->info) rather than alphabetical.

Answer 1

I know this not what you want but you can use code-value based system on that:

{message: 'An error', code : 0, severity: 'error'}
{message: 'A warning', code : 1, severity: 'warning'}
{message: 'Informational message', code : 2, severity: 'info'}

then sort by code.