未处理的拒绝 (TypeError)：无法读取未定义的 属性 'map'

Question

我从developers.themoviedb.org那里得到了对象，但真的很失望有什么问题。
对象发送到浏览器，但我不明白怎么扔给我。
我很困惑，需要帮助
如果在中间件中我写 let arr = JSON.parse(response).results; 也是一个错误：

Unexpected token o in JSON at position 1

response with object in browser

data.service.js

export const getData = (url) => new Promise((resolve, reject) => {
const request = new XMLHttpRequest();
request.open('GET', url);
request.onload = () =>
    (request.status === 200) ?
        resolve(JSON.parse(request.response).results) :
        reject(Error(request.statusText))
  request.onerror = (err) => reject(err)
  request.send();
});

movies.middleware.js

export const moviesMiddleware = store => next => action => {
if (action.type === FETCH_MOVIES_START) {
    getData(popularMovies).then((response) => {
        let arr = response.results;
        let movies = arr.map((item) => {
           return new MovieEntity(item);
        });
        let data = movies;
        store.dispatch({
            type: FETCH_MOVIES_SUCCESS,
            payload: data
        });
    });
  }
  return next(action);
}

movies.action.js

export function fetchMovies() {
return {
    type: FETCH_MOVIES_START
 }
}

Answer 1

您的数据已经是一个对象。无需解析它。并且每次在解析之前检查参数的类型是否为字符串。 ------编辑-----

也试试：

  resolve(
   if(typeOf(request.response)=='string')
    JSON.parse(request.response).results 
   else request.response.results
   )

在movies.middleware.js中修改如下

export const moviesMiddleware = store => next => action => {
if (action.type === FETCH_MOVIES_START) {
    getData(popularMovies).then((response) => {
        let arr = response;
        let movies = arr.map((item) => {
           return new MovieEntity(item);
        });
        let data = movies;
        store.dispatch({
            type: FETCH_MOVIES_SUCCESS,
            payload: data
        });
    });
  }
  return next(action);
}

问题是你正在用 request.response.results 解决 promise 然后你再次以相同的方式访问它 response.result 或者 return request.response 或像上面那样更改访问响应 .