Memory leak when using mathjs in jest tests

[sublayerio]

I noticed unexpected behaviour when using mathjs in Jest.

I created 16 test files that just import mathjs.

When running the tests the memory heap piles up.

[josdejong]

Thanks for reporting Olivier.

At first sight I have no clue what could cause this. Since const mathjs = require('mathjs') is "passive", I doubt whether mathjs itself can instantiate "something" multiple times, nothing is invoked. Is it really mathjs related, or does it occur too with other libraries? As far as I know, inside a single nodejs process, a require is only loaded once. Can it be that Jest does open multiple processes in parallel or so?

[harrysarson]

Can this be reproduced without using Jest?

[harrysarson]

Could Jest run each js file in a separate process (or something)? If so then it would make sense for memory usage to increase.

[sublayerio]

Thanks for your replies.

I think it has to do with running things in parallel and things not getting cleaned up after tests have run. I opened an issue at jest repo as well to figure that out.

jestjs/jest#8832

[josdejong]

Yeah something like that makes sense. It could be that there is no actual problem though and that the garbage collector simply didn't trigger yet.

[gwhitney]

Is there still an issue here four years later, or can this be closed?

[josdejong]

Let's assume it is resolved and close this issue. Please reopen if needed.