Object not initialised in jest `describe`, but initialised in jest `it`

I’m coding a test with jest and I have a long input at the bottom of my test file.
Ideally I’d like to call my function under test once in a describe function and run loads of expect under different it functions.

When trying to access input within an it function, the input is initialised, but not when trying to access it from the body of a describe function.
Does anybody know why this is happening within describe and not it.

I know there are ways around this like move the input higher or move it to another file, but I’m trying to find a solution without doing either of these things.

import myFunction from './my-function';

describe('myFunction', () => {
  /**
   * Accessing myVeryLongInput from here throws:
   * ReferenceError: Cannot access 'myVeryLongInput' before initialization
   */
  const result1 = myFunction(myVeryLongInput);
  it('should update property 2310 to 2319 to be like so', () => {
    /**
     * Accessing myVeryLongInput from here is fine
     */
    const result2 = myFunction(myVeryLongInput);
    expect(result2['2310']).toBe('like so');
    expect(result2['2319']).toBe('like so');
  });
});

const myVeryLongInput = {
  /// 2330 lines of data
}

I know there are ways around this error, but I’m just trying to understand the js closure and scope better