Jest mock localStorage methods

Question

I would like to mock localStorage methods in jest for error simulation. I have localstorage getter and setter methods defined in utility.js. I would like to mock local

Answer 1

This goes inline with what Andreas suggested in the answer, but i was able to mock it using Storage interface. I did something like this,

In jest,

test('throw error', () => {
  Storage.prototype.setItem = jest.fn(() => {
    console.log(" called "); // <-- was called 
    throw new Error('ERROR');
  });

  utility.setItem('123', 'value');
});

Also this PR discussion was helpful.