analytics-node | free way to integrate analytics | Analytics library

You are using Automatic mock by calling jest.mock('analytics-node').

Calling jest.mock('analytics-node') returns a useful "automatic mock" you can use to spy on calls to the class constructor and all of its methods. It replaces the ES6 class with a mock constructor and replaces all of its methods with mock functions that always return undefined. Method calls are saved in theAutomaticMock.mock.instances[index].methodName.mock.calls.

E.g.

index.ts: