Cypress custom command similar to .then() but with retry-ability

commands.ts

declare global {
    namespace Cypress {
        interface Chainable<Subject> {
            /**
             * Custom command similar to cy.then() but with retry-ability
             * @example cy.get('@jsonString').transformValue(JSON.parse).should('deep.equal', expectedValue)
             * Note: If a .should() assertion is successful, the retry chain is stopped.
             * So eg. cy.get('@jsonString').should('exist').transformValue(JSON.parse) will not query the jsonString again once it exists.
             */
            transformValue<T>(transformFn: (subject: Subject) => T): Chainable<T>;
        }
    }
}

Cypress.Commands.addQuery('transformValue', transformFn => {
    return subject => transformFn(subject);
});

example.ts

function extractItem() {
  return cy.window()
    .its('localStorage')
    .invoke('getItem', 'STORED_ITEM')
    .transformValue(item => {
      // We need to put this in an if statement to avoid flooding the logs
      // We also cannot use .should() because it will stop the retry chain and the localStorage will not be queried again
        if (!item) expect(item).to.exist;
        try {
          return JSON.parse(item as string);
        } catch (exception: any) {
          expect.fail(`Error parsing JSON: ${exception.message}`);
        }
    });
}

extractItem.should((item: any[]) => {
  assert.equal(item.length, 42);
};