phawxby / jest-leaking

Minimal repro for Node >=16.11 memory leak

Make sure to npm install first.

Commands

• npm run create - Creates individual test files
• npm run test - Runs tests using jest
• npm run test-vm-script-node - This simply loads a bunch of different modules via vm.Script iteratively based on logging a bunch of files that Jest loads via vm.Script.

Results

Raw results can be found in /results but in summary:

vm.Script

1500 iterations

• 16.10.0 - 3.54MB -> 11.18MB
• 16.11.0 - 3.77MB -> 725.40MB
• 18.4.0 - 4.64MB -> 2758.78MB

Jest

1000 test files

• 16.10.0 - ~100MB - 20s
• 16.11.0 - ~350MB - 40s
• 18.4.0 - ~350MB - 40s

5000 test files

• 16.10.0 - ~100MB - 94s
• 16.11.0 - ~600MB - 220s
• 18.4.0 - ~1200MB - 380s