How to configure a beforeEach function before a test in Jest?

I use beforeEach like this in my tests for React components.

let component;
let configProp;

beforeEach(() => {
  component = shallow(<MyComponent config={configProp} />);
});

Now, I want to change configProp variable in tests. Something like this:

let component;
let configProp;

beforeEach(() => {
  component = shallow(<MyComponent config={configProp} />);
});

test('config_1', () => {
  function firstToRun() {
    // runs beforeEach for this test
    const config_1 = {};
    configProp = config_1;
  }
  expect(component.find({config: config_1}).exists());
})

Is something like this possible? Or, do we have to shallow(<MyComponent />) in every test individually?