如何使用JavaScript Fetch API实现登录后页面跳转？

我使用以下JavaScript代码获取Firebase Token，再通过JavaScript fetch()方法向FastAPI后端发送POST请求完成用户登录。后端验证Token有效后会返回RedirectResponse重定向至另一页面，但浏览器并未执行跳转，仍停留在原页面。

function loginGoogle() {
        var provider = new firebase.auth.GoogleAuthProvider();
        firebase.auth()
            //.currentUser.getToken(provider)
            .signInWithPopup(provider)
            .then((result) => {
                /** @type {firebase.auth.OAuthCredential} */
                var credential = result.credential;

                // This gives you a Google Access Token. You can use it to access the Google API.
                var token = credential.idToken;
            
                // The signed-in user info.
                var user = result.user;
                
                // ...
            })
            .catch((error) => {
                // Handle Errors here.
                var errorCode = error.code;
                var errorMessage = error.message;
                // The email of the user's account used.
                var email = error.email;
                // The firebase.auth.AuthCredential type that was used.
                var credential = error.credential;
                // ...
                
                });

        firebase.auth().currentUser.getIdToken(true).then(function(idToken) {
            console.log(idToken)

            const token = idToken;
            const headers = new Headers({
                    'x-auth-token': token
            });
            const request = new Request('http://localhost:8000/login', {
                    method: 'POST',
                    headers: headers
            });
            fetch(request)
            .then(response => response.json())
            .then(data => console.log(data))
            .catch(error => console.error(error));

         
        })

返回包含登录按钮和loginGoogle函数的登录页面的后端端点：

@router.get("/entrar")
def login(request: Request):
    return templates.TemplateResponse("login.html", {"request": request})

调用上述POST端点后，会重定向至/1这个GET路由，使用的status_code为303，这是FastAPI文档中指定的从POST重定向到GET路由的方式：

@router.post("/login")
async def login(x_auth_token: str = Header(None)):
    valid_token = auth.verify_id_token(x_auth_token)
   
    if valid_token:
        print("token validado")
        return RedirectResponse(url="/1", status_code=status.HTTP_303_SEE_OTHER)
    else:
        return {"msg": "Token no recibido"}

用户应被重定向到的GET端点（跳转未生效）：

@app.get("/1")
def get_landing(request: Request):
    return templates.TemplateResponse("landing.html", {"request": request})

测试/login端点的Swagger截图：

内容的提问来源于stack exchange，提问作者alvaroquin