What are the advantages of Jest over Jasmine?

There are couple of advantages compared to Jasmine:

• Automatically finds tests to execute in your source code.
• Automatically mocks dependencies when running your tests.
• Allows you to test asynchronous code synchronously.
• Runs your tests with a fake DOM implementation (via jsdom) so that your tests can be run on the command line.
• Runs tests in parallel processes so that they finish sooner.

Practical Code Example

// Advantages of Jest: Zero config, parallelized test runs, built-in code coverage, and snapshot testing:
// jest --coverage
test('matches snapshot', () => {
  const tree = renderer.create(<Button label="Save" />).toJSON();
  expect(tree).toMatchSnapshot();
});