Javascript – react js TypeError: JSON.stringfy is not a function

this is my project: When the login button on the login page is clicked, the values ​​entered in the username and password entries will be received with js and a request will be sent to the service at https://fakestoreapi.com/docs#a-login. When a response comes from this service, a redirection will be made to the dashboard from the login page. I’m getting this error in the console "TypeError: JSON.stringfy is not a function"

document.addEventListener("DOMContentLoaded", function() {

  loginform.addEventListener("submit", function(event) {
    event.preventDefault()
    const username = document.getElementById("username").value;
    const password = document.getElementById("password").value;
    const data = {
      username,
      password
    }
    console.log(JSON.stringfy(data))
    fetch('https://fakestoreapi.com/auth/login', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json'
        },
        body: JSON.stringify(data)
      })
      .then(res => res.json())
      .then(json => console.log(json))
      .catch(err => console.log(err.message));
  });
});