jest

Jest cannot parse ES module syntax

SyntaxError.*Unexpected token.*import|Jest.*transform.*failed

Fixes

1.Configure transform in jest.config to use babel-jest or ts-jest
2.Add transformIgnorePatterns to transform specific node_modules packages
3.For ESM packages, add them to transformIgnorePatterns exception list

jesttransformesm

Related Errors

Jest assertion value mismatch

expect\(received\)\.toBe\(expected\)|Expected.*Received

•Check expected vs actual values — use .toEqual() for objects instead of .toBe()
•For floating point, use .toBeCloseTo() instead of exact equality

Jest mock function not called as expected

Expected.*mock.*to have been called|not been called|toHaveBeenCalled

•Verify the mock is injected correctly — check the module path in jest.mock()
•Ensure the code path that calls the function is actually reached

Jest async test timeout

Exceeded timeout.*Async callback|exceeded.*5000.*ms|jest.*timeout

•Ensure async functions resolve: await the promise or call done()
•Increase timeout: jest.setTimeout(10000) or third arg to it()