I am using cypress fixture and intercept to upload a file and also validate if the upload endpoint (post) was successful. here is the code:

describe('something', () => {
 
  let projectID;

  before(() => {
    projectID = localStorage.getItem('projectID');
   
    cy.intercept('POST', '/graphql', (req) => {
      cy.log(req.body);
      if (req.body.operationName === 'postRequest') {
        req.alias = 'postRequest';
      }
    });
  });

  it('should validate file upload', () => {
    const fileName = 'test_file_upload.xlsx';
    cy.get('.file-uploader').should('exist');
    cy.get('.upload-file-label').first().click({ force: true });
    cy.fixture(fileName, 'binary').then((fileContent) => {
      cy.get('input[type=file]')
        .upload(
          {
            fileContent,
            fileName,
            mimeType: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
            encoding: 'utf-8',
          },
          { subjectType: 'input' }
        )
        .wait('@postRequest')
        .then((interception) => {
          cy.log(interception.response.body);
        });
    });
  });
});

I am not exactly sure what is error refer to, but I am guessing it might be async issue.

thank you for your help