Explore @swc/jest as an alternative to ts-jest

[alessbell]

Memory leak issues with jest + ts-jest have been reported since ~2020. There are several open issues on both projects:

• Module caching memory leak kulshekhar/ts-jest#1967
• Memory Leak on ridiculously simple repo jestjs/jest#7874
• [Bug]: Memory consumption issues on Node JS 16.11.0+ jestjs/jest#11956

There are also a number of confounding factors: memory consumption seems to have increased considerably when running this repository's tests in Node.js v16.11+, for example, but the commonly suggested workarounds (using ts-jest's isolatedModules option, jest's --runInBand or any combination of other "fixes") don't solve the issue for Apollo Client's tests.

Running the tests with Node.js v18.9.0 results in a hanging test (#10120).

@swc/jest

I've created the branch swc-jest to explore the use of @swc/jest + @swc/core as a replacement for ts-jest.

[amans1690]

@alessbell I am curious to know why you chose @swc/jest instead of babel-jest as an alternative? Is this just because of performance benefit in case of @swc/jest.

[alessbell]

@amans1690 yes exactly—@swc/jest's perf is really impressive! Unfortunately there are a few things blocking our migration path so we'll be sticking with jest + ts-jest for now. Closing as won't do.