Reproduce memory leak in Jest npm i npm t Recreated without babel-polyfill find . -type d -name '*babel-polyfill*' -print --harmony / --env=node still doesn't help node --harmony ./node_modules/.bin/jest --no-polyfill --logHeapUsage --env=node Suggested setup.js doesn't seem to help: node --harmony node_modules/.bin/jest --env node --setupFilesAfterEnv ./setup.js --logHeapUsage