is history.push() an async call in react?

I am using history object(passed from component to reducer) provided by react in my reducer to conditionally route to other pages while updating the state. I knew thats not how navigation must be handled. But its still working, Is the history.push() function async call as i am executing it before returning modified state in reducer. Can someone explain me why this works

const reducer = (state = initialState, action) => {
var stateClone = {...state};
switch(action.type)
{
  case 'LogIn':
  var user = state.users.filter((user) => user.userName === action.userName && user.password === action.password );
  if(user.length > 0 )
  {
    var loggedInUser = {...user[0]};
    stateClone.loggedInUser = loggedInUser;
    action.history.push('/products');
    return stateClone;
  }
  else {
    alert('Wrong Credentials');
  }
  return state;
}
}